diff --git a/CHANGELOG.md b/CHANGELOG.md
index 271c683..ef41419 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 
 - Fix search crash when the "Tags - Entity" column is displayed
+- Fix tag associate item
 
 ## [2.15.0] - 2026-10-06
 
diff --git a/composer.json b/composer.json
index f1e2ad1..7627874 100644
--- a/composer.json
+++ b/composer.json
@@ -12,6 +12,7 @@
     },
     "autoload": {
         "psr-4": {
+            "GlpiPlugin\\Tag\\": "src/",
             "GlpiPlugin\\Tag\\Tests\\": "tests"
         }
     },
diff --git a/inc/tagitem.class.php b/inc/tagitem.class.php
index dbb924a..8934df1 100644
--- a/inc/tagitem.class.php
+++ b/inc/tagitem.class.php
@@ -197,7 +197,7 @@ public static function showForTag(PluginTagTag $tag)
         if ($canedit) {
             echo "<div class='firstbloc'>";
             echo "<form name='tagitem_form{$rand}' id='tagitem_form{$rand}' method='post'
-               action='" . Toolbox::getItemTypeFormURL('PluginTagTag') . "'>";
+               action='" . Toolbox::getItemTypeFormURL('PluginTagTagItem') . "'>";
 
             echo "<table class='tab_cadre_fixe'>";
             echo "<tr class='tab_bg_2'><th colspan='2'>" . __s('Add an item') . "</th></tr>";
@@ -223,7 +223,7 @@ public static function showForTag(PluginTagTag $tag)
             ]);
             echo "</td><td width='20%'>";
             echo sprintf("<input type='hidden' name='plugin_tag_tags_id' value='%s'>", $instID);
-            echo "<input type='submit' name='add' value=\"" . _sx('button', 'Add') . "\" class='btn btn-primary'>";
+            echo "<input type='submit' name='associate' value=\"" . _sx('button', 'Add') . "\" class='btn btn-primary'>";
             echo "</td></tr>";
 
             echo "</table>";
diff --git a/src/Controller/TagItemController.php b/src/Controller/TagItemController.php
new file mode 100644
index 0000000..6a7a571
--- /dev/null
+++ b/src/Controller/TagItemController.php
@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * -------------------------------------------------------------------------
+ * Tag plugin for GLPI
+ * -------------------------------------------------------------------------
+ *
+ * LICENSE
+ *
+ * This file is part of Tag.
+ *
+ * Tag is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Tag is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Tag. If not, see <http://www.gnu.org/licenses/>.
+ * -------------------------------------------------------------------------
+ * @copyright Copyright (C) 2014-2026 by Teclib'.
+ * @license   GPLv2 https://www.gnu.org/licenses/gpl-2.0.html
+ * @link      https://github.com/pluginsGLPI/tag
+ * -------------------------------------------------------------------------
+ */
+
+namespace GlpiPlugin\Tag\Controller;
+
+use CommonDBTM;
+use Glpi\Controller\GenericFormController;
+use Glpi\Exception\Http\AccessDeniedHttpException;
+use Glpi\Exception\Http\BadRequestHttpException;
+use Glpi\Http\RedirectResponse;
+use Html;
+use PluginTagTag;
+use PluginTagTagItem;
+use Session;
+use Glpi\Routing\Attribute\ItemtypeFormRoute;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+final class TagItemController extends GenericFormController
+{
+    #[ItemtypeFormRoute(PluginTagTagItem::class)]
+    public function associate(Request $request): Response
+    {
+        Session::checkLoginUser();
+
+        $tag_id = $request->request->getInt('plugin_tag_tags_id');
+        $itemtype = $request->request->get('itemtype');
+        $item_id = $request->request->getInt('items_id');
+
+        if (!$tag_id || !$itemtype || !$item_id) {
+            throw new BadRequestHttpException(__s('Missing parameters', 'tag'));
+        }
+
+        $tag = new PluginTagTag();
+        if (!$tag->getFromDB($tag_id) || !$tag->can($tag_id, UPDATE)) {
+            throw new AccessDeniedHttpException(__s('You do not have permission to update this tag', 'tag'));
+        }
+
+        if (!is_a($itemtype, CommonDBTM::class, true) || !PluginTagTag::canItemtype($itemtype)) {
+            throw new BadRequestHttpException(__s('Invalid item type', 'tag'));
+        }
+
+        $item = new $itemtype();
+        if (!$item->getFromDB($item_id) || !$item->canUpdateItem()) {
+            throw new AccessDeniedHttpException(__s('You do not have permission to update this item', 'tag'));
+        }
+
+        $tag_item = new PluginTagTagItem();
+        $found = $tag_item->find([
+            'plugin_tag_tags_id' => $tag_id,
+            'items_id'           => $item_id,
+            'itemtype'           => $itemtype,
+        ]);
+
+        if (count($found) === 0) {
+            $tag_item->add([
+                'plugin_tag_tags_id' => $tag_id,
+                'items_id'           => $item_id,
+                'itemtype'           => $itemtype,
+            ]);
+        }
+
+        return new RedirectResponse(Html::getBackUrl());
+    }
+}
diff --git a/tests/TagTestCase.php b/tests/TagTestCase.php
index 8018c05..34b520f 100644
--- a/tests/TagTestCase.php
+++ b/tests/TagTestCase.php
@@ -46,7 +46,7 @@ protected function logOut()
         $_SESSION['glpi_currenttime'] = $ctime;
     }
 
-    public function loginAs(array $credentials): int
+    public function loginAs(array $credentials, int $rights = READ | CREATE | UPDATE | PURGE): int
     {
         global $DB;
 
@@ -59,7 +59,7 @@ public function loginAs(array $credentials): int
         $DB->update(
             'glpi_profilerights',
             [
-                'rights' => READ | CREATE | UPDATE | PURGE,
+                'rights' => $rights,
             ],
             [
                 'profiles_id' => $user_profile,
@@ -72,17 +72,13 @@ public function loginAs(array $credentials): int
         return $user->getID();
     }
 
-    public function createTag(string $tagName): int
+    public function createTag(string $tagName, array $typeMenu = ['Ticket']): int
     {
-        $tag = new PluginTagTag();
-        $tag->add(
-            [
-                'name' => $tagName,
-                'is_active' => 1,
-                'type_menu' => ['Ticket'],
-            ],
-        );
-        $this->assertGreaterThan(0, $tag->getID());
+        $tag = $this->createItem(PluginTagTag::class, [
+            'name' => $tagName,
+            'is_active' => 1,
+            'type_menu' => $typeMenu,
+        ], ['type_menu']);
 
         return $tag->getID();
     }
diff --git a/tests/Units/TagItemTest.php b/tests/Units/TagItemTest.php
index f700cbe..34bfeba 100644
--- a/tests/Units/TagItemTest.php
+++ b/tests/Units/TagItemTest.php
@@ -30,15 +30,19 @@
 
 namespace GlpiPlugin\Tag\Tests\Units;
 
+use Computer;
+use GlpiPlugin\Tag\Controller\TagItemController;
 use GlpiPlugin\Tag\Tests\TagTestCase;
-use PluginTagTag;
+use Symfony\Component\HttpFoundation\Request;
 use Ticket;
 
 final class TagItemTest extends TagTestCase
 {
+    private const TECH_USER = ['login' => 'tech', 'pass' => 'tech'];
+
     public function testTagsFromTicket(): void
     {
-        $this->login();
+        $this->loginAs(self::TECH_USER);
 
         $tagID1 = $this->createTag('TicketTag1');
         $tagID2 = $this->createTag('TicketTag2');
@@ -58,36 +62,25 @@ public function testTagsFromTicket(): void
         $this->isItemTagged($ticket, $tagID2);
     }
 
-    public function testTagOutOfEntityScopeIsNotLinked(): void
+    public function testTagAssociationCreatesLink(): void
     {
-        $this->login();
+        $this->loginAs(self::TECH_USER);
 
-        $out_of_scope_entity = getItemByTypeName('Entity', '_test_child_2', true);
-        $tag = new PluginTagTag();
-        $tag->add([
-            'name' => 'OutOfScopeTag',
-            'is_active' => 1,
-            'type_menu' => ['Ticket'],
-            'entities_id' => $out_of_scope_entity,
-            'is_recursive' => 0,
+        $tag = $this->createTag('MyTag', ['Computer']);
+        $computer = $this->createItem(Computer::class, [
+            'name' => 'Computer to tag',
+            'entities_id' => 0,
         ]);
-        $tagID = $tag->getID();
-        $this->assertGreaterThan(0, $tagID);
-
-        $this->setEntity('_test_child_1', false);
 
-        $ticket = new Ticket();
-        $ticket->add([
-            'name' => 'Ticket out of scope tag',
-            'content' => 'Ticket out of scope tag',
-            'entities_id' => getItemByTypeName('Entity', '_test_child_1', true),
-            '_plugin_tag_tag_process_form' => 1,
-            '_plugin_tag_tag_values'   => [
-                $tagID,
-            ],
+        $controller = new TagItemController();
+        $request = Request::create('/plugins/tag/associate', 'POST', [
+            'plugin_tag_tags_id' => $tag,
+            'itemtype'           => Computer::class,
+            'items_id'           => $computer->getID(),
         ]);
-        $this->assertGreaterThan(0, $ticket->getID());
 
-        $this->isItemNotTagged($ticket, $tagID);
+        $controller->associate($request);
+
+        $this->isItemTagged($computer, $tag);
     }
 }