diff --git a/common/changes/@microsoft/rush/bmiddha-catalog-aware-preferred-versions_2026-10-13-01-00.json b/common/changes/@microsoft/rush/bmiddha-catalog-aware-preferred-versions_2026-10-13-01-00.json
new file mode 100644
index 0000000000..470636089e
--- /dev/null
+++ b/common/changes/@microsoft/rush/bmiddha-catalog-aware-preferred-versions_2026-10-13-01-00.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Resolve PNPM catalog references (such as \"catalog:\" or \"catalog:tools\") to the catalog versions when Rush calculates implicitly preferred versions. This fixes a \"TypeError: Invalid comparator\" crash in \"rush install\" when a package in the \"preferredVersions\" of common-versions.json is referenced through a catalog, and restores the narrowing of transitive dependency ranges for those packages. \"rush install\" also no longer crashes when a preferred version can't be compared as a SemVer range.",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@microsoft/rush",
+  "email": "223556219+Copilot@users.noreply.github.com"
+}
diff --git a/libraries/rush-lib/src/api/RushConfiguration.ts b/libraries/rush-lib/src/api/RushConfiguration.ts
index 2d2408a9eb..7773b1d8b3 100644
--- a/libraries/rush-lib/src/api/RushConfiguration.ts
+++ b/libraries/rush-lib/src/api/RushConfiguration.ts
@@ -1378,6 +1378,11 @@ export class RushConfiguration {
   /**
    * Returns a map of all direct dependencies that only have a single semantic version specifier.
    *
+   * @remarks
+   * PNPM catalog references (such as `catalog:` or `catalog:tools`) are resolved to the version specifier
+   * from the catalog that is in effect for the subspace of the project that declares the dependency.
+   * Catalog references that don't resolve to a catalog entry are ignored.
+   *
    * @param subspace - The subspace to use
    * @param variant - The name of the current variant in use by the active command.
    *
diff --git a/libraries/rush-lib/src/logic/DependencyAnalyzer.ts b/libraries/rush-lib/src/logic/DependencyAnalyzer.ts
index 93ef26db11..9f389746be 100644
--- a/libraries/rush-lib/src/logic/DependencyAnalyzer.ts
+++ b/libraries/rush-lib/src/logic/DependencyAnalyzer.ts
@@ -8,6 +8,8 @@ import { DependencyType, type PackageJsonDependency } from '../api/PackageJsonEd
 import type { RushConfiguration } from '../api/RushConfiguration';
 import type { RushConfigurationProject } from '../api/RushConfigurationProject';
 import type { Subspace } from '../api/Subspace';
+import { getEffectivePnpmCatalogs, type PnpmCatalogs } from './pnpm/EffectivePnpmOptions';
+import { tryGetPnpmCatalogVersion, tryParsePnpmCatalogName } from './pnpm/PnpmCatalogReference';
 
 export interface IDependencyAnalysis {
   /**
@@ -19,13 +21,32 @@ export interface IDependencyAnalysis {
    * A map of all direct dependencies that only have a single semantic version specifier,
    * unless the {@link CommonVersionsConfiguration.implicitlyPreferredVersions} option
    * set to `false`.
+   *
+   * @remarks
+   * PNPM catalog references (such as `catalog:` or `catalog:tools`) are resolved to the version
+   * specifier from the catalog, so the values are never catalog references.
    */
   implicitlyPreferredVersionByPackageName: Map<string, string>;
 
   /**
    * A map of dependency name to the set of version specifiers used in the repo.
+   *
+   * @remarks
+   * PNPM catalog references are resolved using the catalogs of the subspace that the declaring project
+   * belongs to. A catalog reference that does not resolve (because the catalog has no entry for the
+   * package) is ignored; PNPM reports an error for it when it installs.
    */
   allVersionsByPackageName: Map<string, Set<string>>;
+
+  /**
+   * A map of dependency name to the set of names of the PNPM catalogs that projects reference the
+   * dependency through, for example `default` for `catalog:` and `tools` for `catalog:tools`.
+   *
+   * @remarks
+   * Only catalog references that resolve are included. A dependency that no project references
+   * through a catalog does not have an entry.
+   */
+  catalogNamesByPackageName: Map<string, Set<string>>;
 }
 
 let _dependencyAnalyzerByRushConfiguration: WeakMap<RushConfiguration, DependencyAnalyzer> | undefined;
@@ -103,6 +124,25 @@ export class DependencyAnalyzer {
       ReadonlyArray<string>
     > = commonVersionsConfiguration.allowedAlternativeVersions;
 
+    const catalogNamesByPackageName: Map<string, Set<string>> = new Map();
+
+    // The catalogs can differ between subspaces, so each catalog reference must be resolved using the
+    // catalogs of the declaring project's subspace. These are only loaded for projects that use catalogs.
+    const catalogsBySubspace: Map<Subspace, PnpmCatalogs | undefined> = new Map();
+    const getCatalogsForProject: (project: RushConfigurationProject) => PnpmCatalogs | undefined = (
+      project: RushConfigurationProject
+    ) => {
+      const projectSubspace: Subspace = project.subspace;
+      if (!catalogsBySubspace.has(projectSubspace)) {
+        catalogsBySubspace.set(
+          projectSubspace,
+          getEffectivePnpmCatalogs(projectSubspace, this.#rushConfiguration)
+        );
+      }
+
+      return catalogsBySubspace.get(projectSubspace);
+    };
+
     let projectsToProcess: RushConfigurationProject[] = this.#rushConfiguration.projects;
     if (addAction && this.#rushConfiguration.subspacesFeatureEnabled) {
       projectsToProcess = subspace.getProjects();
@@ -113,13 +153,32 @@ export class DependencyAnalyzer {
         ...project.packageJsonEditor.dependencyList,
         ...project.packageJsonEditor.devDependencyList
       ];
-      for (const { name: dependencyName, version: dependencyVersion, dependencyType } of dependencies) {
+      for (const { name: dependencyName, version: specifiedVersion, dependencyType } of dependencies) {
         if (dependencyType === DependencyType.Peer) {
           // If this is a peer dependency, it isn't a real dependency in this context, so it shouldn't
           // be included in the list of dependency versions.
           continue;
         }
 
+        let dependencyVersion: string = specifiedVersion;
+        const catalogName: string | undefined = tryParsePnpmCatalogName(specifiedVersion);
+        if (catalogName !== undefined) {
+          // This is a PNPM catalog reference such as "catalog:" or "catalog:tools". Use the version
+          // from the catalog, since that is the version that PNPM installs.
+          const catalogVersion: string | undefined = tryGetPnpmCatalogVersion(
+            getCatalogsForProject(project),
+            catalogName,
+            dependencyName
+          );
+          if (catalogVersion === undefined) {
+            // The catalog doesn't have an entry for this package. PNPM reports an error for this when it
+            // installs, so ignore it here rather than treating "catalog:" as a version specifier.
+            continue;
+          }
+
+          dependencyVersion = catalogVersion;
+        }
+
         if (dependencyVersion.startsWith('workspace:')) {
           // If this is a workspace protocol dependency, ignore it.
           continue;
@@ -145,6 +204,17 @@ export class DependencyAnalyzer {
         }
 
         allVersionForDependency.add(dependencyVersion);
+
+        if (catalogName !== undefined) {
+          let catalogNamesForDependency: Set<string> | undefined =
+            catalogNamesByPackageName.get(dependencyName);
+          if (!catalogNamesForDependency) {
+            catalogNamesForDependency = new Set<string>();
+            catalogNamesByPackageName.set(dependencyName, catalogNamesForDependency);
+          }
+
+          catalogNamesForDependency.add(catalogName);
+        }
       }
     }
 
@@ -190,7 +260,8 @@ export class DependencyAnalyzer {
     return {
       commonVersionsConfiguration,
       implicitlyPreferredVersionByPackageName,
-      allVersionsByPackageName
+      allVersionsByPackageName,
+      catalogNamesByPackageName
     };
   }
 }
diff --git a/libraries/rush-lib/src/logic/pnpm/PnpmCatalogReference.ts b/libraries/rush-lib/src/logic/pnpm/PnpmCatalogReference.ts
new file mode 100644
index 0000000000..7795096f76
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/PnpmCatalogReference.ts
@@ -0,0 +1,96 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
+// See LICENSE in the project root for license information.
+
+import type { PnpmCatalogs } from './EffectivePnpmOptions';
+
+/**
+ * The prefix of a version specifier that references a PNPM catalog, e.g. `catalog:` or `catalog:tools`.
+ */
+export const PNPM_CATALOG_PROTOCOL: 'catalog:' = 'catalog:';
+
+/**
+ * The name of the catalog that `catalog:` refers to.
+ */
+export const DEFAULT_PNPM_CATALOG_NAME: 'default' = 'default';
+
+/**
+ * A package.json version specifier that references a PNPM catalog, and the catalog entry it resolves to.
+ */
+export interface IPnpmCatalogReference {
+  /**
+   * The normalized name of the referenced catalog. Both `catalog:` and `catalog:default` reference
+   * the catalog named `default`.
+   */
+  readonly catalogName: string;
+
+  /**
+   * The version specifier from the catalog entry for the package, for example `~5.8.2`.
+   * This is `undefined` if the referenced catalog does not exist or does not have an entry for the package.
+   * PNPM reports an error for such references when it installs.
+   */
+  readonly resolvedVersion: string | undefined;
+}
+
+/**
+ * If the version specifier references a PNPM catalog, returns the normalized name of the catalog.
+ * Otherwise, returns `undefined`.
+ *
+ * @remarks
+ * This matches how PNPM parses the catalog protocol: the catalog name is trimmed, and `catalog:`
+ * (with an empty name) references the `default` catalog, the same as `catalog:default`.
+ */
+export function tryParsePnpmCatalogName(versionSpecifier: string): string | undefined {
+  if (!versionSpecifier.startsWith(PNPM_CATALOG_PROTOCOL)) {
+    return undefined;
+  }
+
+  const catalogName: string = versionSpecifier.slice(PNPM_CATALOG_PROTOCOL.length).trim();
+  return catalogName || DEFAULT_PNPM_CATALOG_NAME;
+}
+
+/**
+ * Returns the version specifier of the entry for the package in the specified catalog, or `undefined`
+ * if that catalog does not exist or does not have an entry for the package.
+ */
+export function tryGetPnpmCatalogVersion(
+  catalogs: PnpmCatalogs | undefined,
+  catalogName: string,
+  packageName: string
+): string | undefined {
+  // Use own-property checks so that names like "constructor" don't resolve to Object.prototype members
+  if (!catalogs || !Object.prototype.hasOwnProperty.call(catalogs, catalogName)) {
+    return undefined;
+  }
+
+  const catalog: Record<string, string> = catalogs[catalogName];
+  if (!Object.prototype.hasOwnProperty.call(catalog, packageName)) {
+    return undefined;
+  }
+
+  return catalog[packageName];
+}
+
+/**
+ * If the version specifier for the package references a PNPM catalog, returns the referenced catalog
+ * and the version specifier that the reference resolves to. Otherwise, returns `undefined`.
+ *
+ * @param packageName - the dependency package name, i.e. the key from a "dependencies" table
+ * @param versionSpecifier - the dependency version specifier, i.e. the value from a "dependencies" table
+ * @param catalogs - the catalogs that are in effect for the subspace of the project that declares the
+ * dependency, as returned by `getEffectivePnpmCatalogs()`
+ */
+export function tryResolvePnpmCatalogReference(
+  packageName: string,
+  versionSpecifier: string,
+  catalogs: PnpmCatalogs | undefined
+): IPnpmCatalogReference | undefined {
+  const catalogName: string | undefined = tryParsePnpmCatalogName(versionSpecifier);
+  if (catalogName === undefined) {
+    return undefined;
+  }
+
+  return {
+    catalogName,
+    resolvedVersion: tryGetPnpmCatalogVersion(catalogs, catalogName, packageName)
+  };
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/PnpmfileConfiguration.ts b/libraries/rush-lib/src/logic/pnpm/PnpmfileConfiguration.ts
index 8f2c4cebeb..4cb9e6e3d9 100644
--- a/libraries/rush-lib/src/logic/pnpm/PnpmfileConfiguration.ts
+++ b/libraries/rush-lib/src/logic/pnpm/PnpmfileConfiguration.ts
@@ -114,8 +114,16 @@ async function _getPnpmfileShimSettingsAsync(
       rushConfiguration.getImplicitlyPreferredVersions(subspace, variant)
     );
     for (const [name, version] of commonVersionsConfiguration.getAllPreferredVersions()) {
-      // Use the most restrictive version range available
-      if (!preferredVersions.has(name) || semver.subset(version, preferredVersions.get(name)!)) {
+      // Use the most restrictive version range available. If the two version specifiers can't be
+      // compared (for example, because one of them is an "npm:" alias or a git URL), the explicitly
+      // preferred version wins.
+      const implicitlyPreferredVersion: string | undefined = preferredVersions.get(name);
+      if (
+        implicitlyPreferredVersion === undefined ||
+        !semver.validRange(version) ||
+        !semver.validRange(implicitlyPreferredVersion) ||
+        semver.subset(version, implicitlyPreferredVersion)
+      ) {
         preferredVersions.set(name, version);
       }
     }
diff --git a/libraries/rush-lib/src/logic/pnpm/test/PnpmCatalogReference.test.ts b/libraries/rush-lib/src/logic/pnpm/test/PnpmCatalogReference.test.ts
new file mode 100644
index 0000000000..1d2fb46bec
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/PnpmCatalogReference.test.ts
@@ -0,0 +1,105 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
+// See LICENSE in the project root for license information.
+
+import {
+  DEFAULT_PNPM_CATALOG_NAME,
+  tryGetPnpmCatalogVersion,
+  tryParsePnpmCatalogName,
+  tryResolvePnpmCatalogReference
+} from '../PnpmCatalogReference';
+import type { PnpmCatalogs } from '../EffectivePnpmOptions';
+
+const CATALOGS: PnpmCatalogs = {
+  default: {
+    typescript: '~5.8.2'
+  },
+  tools: {
+    eslint: '~9.37.0'
+  }
+};
+
+describe('PnpmCatalogReference', () => {
+  describe(tryParsePnpmCatalogName.name, () => {
+    it('maps "catalog:" and "catalog:default" to the default catalog', () => {
+      expect(tryParsePnpmCatalogName('catalog:')).toBe(DEFAULT_PNPM_CATALOG_NAME);
+      expect(tryParsePnpmCatalogName('catalog:default')).toBe(DEFAULT_PNPM_CATALOG_NAME);
+    });
+
+    it('returns the name of a named catalog', () => {
+      expect(tryParsePnpmCatalogName('catalog:tools')).toBe('tools');
+    });
+
+    it('trims the catalog name, like PNPM does', () => {
+      expect(tryParsePnpmCatalogName('catalog: tools ')).toBe('tools');
+      expect(tryParsePnpmCatalogName('catalog: ')).toBe(DEFAULT_PNPM_CATALOG_NAME);
+    });
+
+    it('returns undefined for version specifiers that are not catalog references', () => {
+      for (const versionSpecifier of [
+        '~5.8.2',
+        '',
+        'workspace:*',
+        'npm:typescript@~5.8.2',
+        'file:../typescript',
+        'catalog',
+        ' catalog:'
+      ]) {
+        expect(tryParsePnpmCatalogName(versionSpecifier)).toBeUndefined();
+      }
+    });
+  });
+
+  describe(tryGetPnpmCatalogVersion.name, () => {
+    it('returns the version from the catalog entry', () => {
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'default', 'typescript')).toBe('~5.8.2');
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'tools', 'eslint')).toBe('~9.37.0');
+    });
+
+    it('returns undefined if the catalog or the entry does not exist', () => {
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'default', 'eslint')).toBeUndefined();
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'nonexistent', 'typescript')).toBeUndefined();
+      expect(tryGetPnpmCatalogVersion(undefined, 'default', 'typescript')).toBeUndefined();
+    });
+
+    it('does not resolve Object.prototype members', () => {
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'constructor', 'name')).toBeUndefined();
+      expect(tryGetPnpmCatalogVersion(CATALOGS, 'default', 'toString')).toBeUndefined();
+    });
+  });
+
+  describe(tryResolvePnpmCatalogReference.name, () => {
+    it('resolves catalog references', () => {
+      expect(tryResolvePnpmCatalogReference('typescript', 'catalog:', CATALOGS)).toEqual({
+        catalogName: 'default',
+        resolvedVersion: '~5.8.2'
+      });
+      expect(tryResolvePnpmCatalogReference('typescript', 'catalog:default', CATALOGS)).toEqual({
+        catalogName: 'default',
+        resolvedVersion: '~5.8.2'
+      });
+      expect(tryResolvePnpmCatalogReference('eslint', 'catalog:tools', CATALOGS)).toEqual({
+        catalogName: 'tools',
+        resolvedVersion: '~9.37.0'
+      });
+    });
+
+    it('reports a catalog reference that does not resolve', () => {
+      expect(tryResolvePnpmCatalogReference('missing', 'catalog:', CATALOGS)).toEqual({
+        catalogName: 'default',
+        resolvedVersion: undefined
+      });
+      expect(tryResolvePnpmCatalogReference('typescript', 'catalog:nonexistent', CATALOGS)).toEqual({
+        catalogName: 'nonexistent',
+        resolvedVersion: undefined
+      });
+      expect(tryResolvePnpmCatalogReference('typescript', 'catalog:', undefined)).toEqual({
+        catalogName: 'default',
+        resolvedVersion: undefined
+      });
+    });
+
+    it('returns undefined for version specifiers that are not catalog references', () => {
+      expect(tryResolvePnpmCatalogReference('typescript', '~5.8.2', CATALOGS)).toBeUndefined();
+    });
+  });
+});
diff --git a/libraries/rush-lib/src/logic/pnpm/test/PnpmShrinkwrapFile.test.ts b/libraries/rush-lib/src/logic/pnpm/test/PnpmShrinkwrapFile.test.ts
index e54732aa3b..e56fdc60ee 100644
--- a/libraries/rush-lib/src/logic/pnpm/test/PnpmShrinkwrapFile.test.ts
+++ b/libraries/rush-lib/src/logic/pnpm/test/PnpmShrinkwrapFile.test.ts
@@ -769,6 +769,39 @@ snapshots:
         ).resolves.toBe(false);
       });
 
+      it('can detect not modified when dependencies reference catalogs', async () => {
+        // The project's package.json and the lockfile both use "catalog:", "catalog:default", and
+        // "catalog:tools" specifiers, and common-versions.json has preferredVersions for some of them
+        const project = getMockRushProjectWithCatalogs();
+        const pnpmShrinkwrapFile = getPnpmShrinkwrapFileFromFile(
+          `${__dirname}/yamlFiles/pnpm-lock-v9/catalogs-not-modified.yaml`,
+          project.rushConfiguration.defaultSubspace
+        );
+        await expect(
+          pnpmShrinkwrapFile.isWorkspaceProjectModifiedAsync(
+            project,
+            project.rushConfiguration.defaultSubspace,
+            undefined
+          )
+        ).resolves.toBe(false);
+      });
+
+      it('can detect modified when a dependency was changed to reference a catalog', async () => {
+        // The lockfile records "typescript" with the "~5.8.2" specifier, but the project now uses "catalog:"
+        const project = getMockRushProjectWithCatalogs();
+        const pnpmShrinkwrapFile = getPnpmShrinkwrapFileFromFile(
+          `${__dirname}/yamlFiles/pnpm-lock-v9/catalogs-modified.yaml`,
+          project.rushConfiguration.defaultSubspace
+        );
+        await expect(
+          pnpmShrinkwrapFile.isWorkspaceProjectModifiedAsync(
+            project,
+            project.rushConfiguration.defaultSubspace,
+            undefined
+          )
+        ).resolves.toBe(true);
+      });
+
       it('can detect a devDependency that is still listed under dependencies in the importer', async () => {
         // Regression: moving a dep from dependencies to devDependencies should be detected as modified.
         const project = getMockRushProject();
@@ -879,3 +912,13 @@ function getMockRushProject2(): RushConfigurationProject {
   }
   return project;
 }
+
+function getMockRushProjectWithCatalogs(): RushConfigurationProject {
+  const rushFilename: string = `${__dirname}/repoWithCatalogs/rush.json`;
+  const rushConfiguration = RushConfiguration.loadFromConfigurationFile(rushFilename);
+  const project = rushConfiguration.projectsByName.get('app-a');
+  if (!project) {
+    throw new Error(`Can not get project "app-a"`);
+  }
+  return project;
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/PnpmfileConfiguration.test.ts b/libraries/rush-lib/src/logic/pnpm/test/PnpmfileConfiguration.test.ts
index 23dafd9caf..c5779489ef 100644
--- a/libraries/rush-lib/src/logic/pnpm/test/PnpmfileConfiguration.test.ts
+++ b/libraries/rush-lib/src/logic/pnpm/test/PnpmfileConfiguration.test.ts
@@ -1,9 +1,11 @@
 // Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
 // See LICENSE in the project root for license information.
 
+import { type IPackageJson, JsonFile, type JsonObject } from '@rushstack/node-core-library';
+
 import { RushConfiguration } from '../../../api/RushConfiguration';
+import type { RushConfigurationProject } from '../../../api/RushConfigurationProject';
 import { PnpmfileConfiguration } from '../PnpmfileConfiguration';
-import { JsonFile, type JsonObject } from '@rushstack/node-core-library';
 
 describe(PnpmfileConfiguration.name, () => {
   const repoPath: string = `${__dirname}/repo`;
@@ -35,4 +37,81 @@ describe(PnpmfileConfiguration.name, () => {
     const shimJson: JsonObject = await JsonFile.loadAsync(shimPath);
     expect(shimJson.allPreferredVersions).toHaveProperty('find-up', '5.0.0');
   });
+
+  describe('with PNPM catalogs', () => {
+    // The catalogs define "typescript": "~5.8.2", "tslib": "~2.3.1", and "eslint": "~9.37.0" (in the "tools"
+    // catalog), and common-versions.json has preferredVersions for "typescript" and "eslint". Projects reference
+    // these packages through "catalog:", "catalog:default", and "catalog:tools".
+    const catalogRushConfiguration: RushConfiguration = RushConfiguration.loadFromConfigurationFile(
+      `${__dirname}/repoWithCatalogs/rush.json`
+    );
+    const catalogShimPath: string = `${catalogRushConfiguration.defaultSubspace.getSubspaceTempFolderPath()}/pnpmfileSettings.json`;
+
+    it('does not crash when a package in preferredVersions is referenced through a catalog', async () => {
+      const subspace = catalogRushConfiguration.defaultSubspace;
+      await PnpmfileConfiguration.writeCommonTempPnpmfileShimAsync(
+        catalogRushConfiguration,
+        subspace.getSubspaceTempFolderPath(),
+        subspace,
+        undefined
+      );
+
+      const shimJson: JsonObject = await JsonFile.loadAsync(catalogShimPath);
+      expect(shimJson.allPreferredVersions).toEqual({
+        typescript: '~5.8.2',
+        tslib: '~2.3.1',
+        eslint: '~9.37.0',
+        // The implicitly preferred version is an "npm:" alias, which can't be compared with the explicitly
+        // preferred version, so the explicitly preferred version wins
+        'aliased-dep': '^1.0.0',
+        // The explicitly preferred version is a git URL, which can't be compared with the implicitly
+        // preferred version, so the explicitly preferred version wins
+        'git-dep': 'git+https://github.com/example/git-dep.git'
+      });
+    });
+
+    it('narrows the dependency ranges of external packages to the catalog versions', async () => {
+      const pnpmfileConfiguration: PnpmfileConfiguration = await PnpmfileConfiguration.initializeAsync(
+        catalogRushConfiguration,
+        catalogRushConfiguration.defaultSubspace,
+        undefined
+      );
+
+      const transformed: IPackageJson = pnpmfileConfiguration.transform({
+        name: 'some-external-package',
+        version: '1.0.0',
+        dependencies: {
+          typescript: '^5.0.0',
+          tslib: '^2.0.0',
+          eslint: '^9.0.0'
+        }
+      });
+      expect(transformed.dependencies).toEqual({
+        typescript: '~5.8.2',
+        tslib: '~2.3.1',
+        eslint: '~9.37.0'
+      });
+    });
+
+    it("does not rewrite a workspace project's catalog references", async () => {
+      const pnpmfileConfiguration: PnpmfileConfiguration = await PnpmfileConfiguration.initializeAsync(
+        catalogRushConfiguration,
+        catalogRushConfiguration.defaultSubspace,
+        undefined
+      );
+
+      const project: RushConfigurationProject = catalogRushConfiguration.getProjectByName('app-a')!;
+      const transformed: IPackageJson = pnpmfileConfiguration.transform(
+        project.packageJsonEditor.saveToObject()
+      );
+      expect(transformed.dependencies).toEqual({
+        'lib-b': 'workspace:*',
+        tslib: 'catalog:default',
+        typescript: 'catalog:'
+      });
+      expect(transformed.devDependencies).toEqual({
+        eslint: 'catalog:tools'
+      });
+    });
+  });
 });
diff --git a/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/apps/app-a/package.json b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/apps/app-a/package.json
new file mode 100644
index 0000000000..dac0d8fff2
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/apps/app-a/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "app-a",
+  "version": "1.0.0",
+  "dependencies": {
+    "lib-b": "workspace:*",
+    "tslib": "catalog:default",
+    "typescript": "catalog:"
+  },
+  "devDependencies": {
+    "eslint": "catalog:tools"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/common-versions.json b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/common-versions.json
new file mode 100644
index 0000000000..a37f7447be
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/common-versions.json
@@ -0,0 +1,9 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/common-versions.schema.json",
+  "preferredVersions": {
+    "typescript": "~5.8.2",
+    "eslint": "~9.37.0",
+    "aliased-dep": "^1.0.0",
+    "git-dep": "git+https://github.com/example/git-dep.git"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/pnpm-config.json b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/pnpm-config.json
new file mode 100644
index 0000000000..bb05c081e8
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/common/config/rush/pnpm-config.json
@@ -0,0 +1,13 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/pnpm-config.schema.json",
+  "useWorkspaces": true,
+  "globalCatalogs": {
+    "default": {
+      "typescript": "~5.8.2",
+      "tslib": "~2.3.1"
+    },
+    "tools": {
+      "eslint": "~9.37.0"
+    }
+  }
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/libs/lib-b/package.json b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/libs/lib-b/package.json
new file mode 100644
index 0000000000..0276bd1727
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/libs/lib-b/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "lib-b",
+  "version": "1.0.0",
+  "dependencies": {
+    "aliased-dep": "npm:real-dep@^1.0.0",
+    "git-dep": "^2.0.0",
+    "missing-entry": "catalog:",
+    "tslib": "catalog:"
+  },
+  "devDependencies": {
+    "missing-catalog": "catalog:nonexistent",
+    "typescript": "~5.8.2"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/rush.json b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/rush.json
new file mode 100644
index 0000000000..47863ff0ca
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/repoWithCatalogs/rush.json
@@ -0,0 +1,17 @@
+{
+  "pnpmVersion": "9.15.0",
+  "rushVersion": "5.46.1",
+  "projectFolderMinDepth": 1,
+  "projectFolderMaxDepth": 99,
+
+  "projects": [
+    {
+      "packageName": "app-a",
+      "projectFolder": "apps/app-a"
+    },
+    {
+      "packageName": "lib-b",
+      "projectFolder": "libs/lib-b"
+    }
+  ]
+}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-modified.yaml b/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-modified.yaml
new file mode 100644
index 0000000000..42402f3694
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-modified.yaml
@@ -0,0 +1,65 @@
+lockfileVersion: '9.0'
+
+settings:
+  autoInstallPeers: true
+  excludeLinksFromLockfile: false
+
+catalogs:
+  default:
+    tslib:
+      specifier: ~2.3.1
+      version: 2.3.1
+    typescript:
+      specifier: ~5.8.2
+      version: 5.8.3
+  tools:
+    eslint:
+      specifier: ~9.37.0
+      version: 9.37.0
+
+importers:
+  .: {}
+
+  ../../apps/app-a:
+    dependencies:
+      lib-b:
+        specifier: workspace:*
+        version: link:../../libs/lib-b
+      tslib:
+        specifier: catalog:default
+        version: 2.3.1
+      typescript:
+        specifier: ~5.8.2
+        version: 5.8.3
+    devDependencies:
+      eslint:
+        specifier: catalog:tools
+        version: 9.37.0
+
+packages:
+  eslint@9.37.0:
+    resolution:
+      {
+        integrity: sha512-XyLmROnACWqSxiGYArdef1fItQd47weqB7iwtfr9JHwRrqIXZdcFMvvEcL9xHCmL0SNsOvF0c42lWyM1U5dgig==
+      }
+
+  tslib@2.3.1:
+    resolution:
+      {
+        integrity: sha512-77EbyPPpMz+FRFRuAFlWMtmgUWGe9UOG2Z25NqCwiIjRhOf5iKGuzSe5P2w1laq+FkRy4p+PCuVkJSGkzTEKVw==
+      }
+
+  typescript@5.8.3:
+    resolution:
+      {
+        integrity: sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==
+      }
+    engines: { node: '>=14.17' }
+    hasBin: true
+
+snapshots:
+  eslint@9.37.0: {}
+
+  tslib@2.3.1: {}
+
+  typescript@5.8.3: {}
diff --git a/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-not-modified.yaml b/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-not-modified.yaml
new file mode 100644
index 0000000000..55bae5ebf3
--- /dev/null
+++ b/libraries/rush-lib/src/logic/pnpm/test/yamlFiles/pnpm-lock-v9/catalogs-not-modified.yaml
@@ -0,0 +1,65 @@
+lockfileVersion: '9.0'
+
+settings:
+  autoInstallPeers: true
+  excludeLinksFromLockfile: false
+
+catalogs:
+  default:
+    tslib:
+      specifier: ~2.3.1
+      version: 2.3.1
+    typescript:
+      specifier: ~5.8.2
+      version: 5.8.3
+  tools:
+    eslint:
+      specifier: ~9.37.0
+      version: 9.37.0
+
+importers:
+  .: {}
+
+  ../../apps/app-a:
+    dependencies:
+      lib-b:
+        specifier: workspace:*
+        version: link:../../libs/lib-b
+      tslib:
+        specifier: catalog:default
+        version: 2.3.1
+      typescript:
+        specifier: 'catalog:'
+        version: 5.8.3
+    devDependencies:
+      eslint:
+        specifier: catalog:tools
+        version: 9.37.0
+
+packages:
+  eslint@9.37.0:
+    resolution:
+      {
+        integrity: sha512-XyLmROnACWqSxiGYArdef1fItQd47weqB7iwtfr9JHwRrqIXZdcFMvvEcL9xHCmL0SNsOvF0c42lWyM1U5dgig==
+      }
+
+  tslib@2.3.1:
+    resolution:
+      {
+        integrity: sha512-77EbyPPpMz+FRFRuAFlWMtmgUWGe9UOG2Z25NqCwiIjRhOf5iKGuzSe5P2w1laq+FkRy4p+PCuVkJSGkzTEKVw==
+      }
+
+  typescript@5.8.3:
+    resolution:
+      {
+        integrity: sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==
+      }
+    engines: { node: '>=14.17' }
+    hasBin: true
+
+snapshots:
+  eslint@9.37.0: {}
+
+  tslib@2.3.1: {}
+
+  typescript@5.8.3: {}
diff --git a/libraries/rush-lib/src/logic/test/DependencyAnalyzer.test.ts b/libraries/rush-lib/src/logic/test/DependencyAnalyzer.test.ts
index 04f192fef8..e4dcaf334e 100644
--- a/libraries/rush-lib/src/logic/test/DependencyAnalyzer.test.ts
+++ b/libraries/rush-lib/src/logic/test/DependencyAnalyzer.test.ts
@@ -2,6 +2,7 @@
 // See LICENSE in the project root for license information.
 
 import { RushConfiguration } from '../../api/RushConfiguration';
+import type { Subspace } from '../../api/Subspace';
 import { DependencyAnalyzer, type IDependencyAnalysis } from '../DependencyAnalyzer';
 
 describe(DependencyAnalyzer.name, () => {
@@ -88,4 +89,139 @@ describe(DependencyAnalyzer.name, () => {
       }
     `);
   });
+
+  describe('PNPM catalogs', () => {
+    function getAnalysisForRushJson(
+      rushJsonPath: string,
+      subspaceName?: string,
+      addAction: boolean = false
+    ): IDependencyAnalysis {
+      const rushConfiguration: RushConfiguration = RushConfiguration.loadFromConfigurationFile(rushJsonPath);
+      const subspace: Subspace | undefined = subspaceName
+        ? rushConfiguration.getSubspace(subspaceName)
+        : undefined;
+      return DependencyAnalyzer.forRushConfiguration(rushConfiguration).getAnalysis(
+        subspace,
+        undefined,
+        addAction
+      );
+    }
+
+    it('resolves references to the default and named catalogs', () => {
+      const analysis: IDependencyAnalysis = getAnalysisForRushJson(`${__dirname}/repoWithCatalogs/rush.json`);
+      expect(analysis.allVersionsByPackageName).toEqual(
+        new Map([
+          ['react', new Set(['^18.0.0'])],
+          ['semver', new Set(['^7.5.4'])],
+          ['typescript', new Set(['~5.3.0'])],
+          ['eslint', new Set(['^8.50.0'])]
+        ])
+      );
+      expect(analysis.implicitlyPreferredVersionByPackageName).toEqual(
+        new Map([
+          ['react', '^18.0.0'],
+          ['semver', '^7.5.4'],
+          ['typescript', '~5.3.0'],
+          ['eslint', '^8.50.0']
+        ])
+      );
+      expect(analysis.catalogNamesByPackageName).toEqual(
+        new Map([
+          ['react', new Set(['default'])],
+          ['semver', new Set(['default'])],
+          ['typescript', new Set(['tools'])],
+          ['eslint', new Set(['tools'])]
+        ])
+      );
+    });
+
+    it('treats "catalog:default" like "catalog:", and ignores catalog references that do not resolve', () => {
+      // app-a uses "tslib": "catalog:default" and "typescript": "catalog:"
+      // lib-b uses "tslib": "catalog:", a literal "typescript": "~5.8.2", and references
+      // a catalog entry and a catalog that don't exist
+      const analysis: IDependencyAnalysis = getAnalysisForRushJson(
+        `${__dirname}/../pnpm/test/repoWithCatalogs/rush.json`
+      );
+      expect(analysis.allVersionsByPackageName).toEqual(
+        new Map([
+          ['tslib', new Set(['~2.3.1'])],
+          ['typescript', new Set(['~5.8.2'])],
+          ['eslint', new Set(['~9.37.0'])],
+          ['aliased-dep', new Set(['npm:real-dep@^1.0.0'])],
+          ['git-dep', new Set(['^2.0.0'])]
+        ])
+      );
+      expect(analysis.implicitlyPreferredVersionByPackageName).toEqual(
+        new Map([
+          ['tslib', '~2.3.1'],
+          ['typescript', '~5.8.2'],
+          ['eslint', '~9.37.0'],
+          ['aliased-dep', 'npm:real-dep@^1.0.0'],
+          ['git-dep', '^2.0.0']
+        ])
+      );
+      expect(analysis.catalogNamesByPackageName).toEqual(
+        new Map([
+          ['tslib', new Set(['default'])],
+          ['typescript', new Set(['default'])],
+          ['eslint', new Set(['tools'])]
+        ])
+      );
+    });
+
+    it("resolves catalog references using the catalogs of each project's subspace", () => {
+      // a (default subspace) and e (own-config-subspace) both use "react": "catalog:", but the
+      // catalogs resolve it to different versions. c (other-subspace) falls back to the common catalogs.
+      const analysis: IDependencyAnalysis = getAnalysisForRushJson(
+        `${__dirname}/repoWithSubspacesCommonCatalogs/rush.json`
+      );
+      expect(analysis.allVersionsByPackageName).toEqual(
+        new Map([
+          ['react', new Set(['^18.0.0', '^17.0.0'])],
+          ['typescript', new Set(['~5.3.0'])],
+          ['foo', new Set(['~2.0.0'])],
+          ['lodash', new Set(['^4.17.0'])]
+        ])
+      );
+      expect(analysis.implicitlyPreferredVersionByPackageName).toEqual(
+        new Map([
+          ['typescript', '~5.3.0'],
+          ['foo', '~2.0.0'],
+          ['lodash', '^4.17.0']
+        ])
+      );
+      expect(analysis.catalogNamesByPackageName).toEqual(
+        new Map([
+          ['react', new Set(['default'])],
+          ['typescript', new Set(['tools'])],
+          ['foo', new Set(['default'])]
+        ])
+      );
+    });
+
+    it('resolves catalog references using the subspace catalogs for "rush add"', () => {
+      const ownConfigAnalysis: IDependencyAnalysis = getAnalysisForRushJson(
+        `${__dirname}/repoWithSubspacesCommonCatalogs/rush.json`,
+        'own-config-subspace',
+        true
+      );
+      expect(ownConfigAnalysis.allVersionsByPackageName).toEqual(new Map([['react', new Set(['^17.0.0'])]]));
+      expect(ownConfigAnalysis.implicitlyPreferredVersionByPackageName).toEqual(
+        new Map([['react', '^17.0.0']])
+      );
+
+      const otherAnalysis: IDependencyAnalysis = getAnalysisForRushJson(
+        `${__dirname}/repoWithSubspacesCommonCatalogs/rush.json`,
+        'other-subspace',
+        true
+      );
+      expect(otherAnalysis.implicitlyPreferredVersionByPackageName).toEqual(
+        new Map([
+          ['foo', '~2.0.0'],
+          ['lodash', '^4.17.0']
+        ])
+      );
+      expect(otherAnalysis.catalogNamesByPackageName).toEqual(new Map([['foo', new Set(['default'])]]));
+    });
+  });
 });