diff --git a/lib/private/Comments/Comment.php b/lib/private/Comments/Comment.php
index c239958b08060..a5f7526580183 100644
--- a/lib/private/Comments/Comment.php
+++ b/lib/private/Comments/Comment.php
@@ -196,7 +196,8 @@ public function setMessage($message, $maxLength = self::MAX_MESSAGE_LENGTH): ICo
 	 *
 	 * @param bool $supportMarkdown
 	 * @return array each mention provides a 'type' and an 'id', see example below
-	 * @psalm-return list<array{type: 'guest'|'email'|'federated_group'|'group'|'federated_team'|'team'|'federated_user'|'user', id: non-empty-lowercase-string}>
+	 * @psalm-return list<array{type: 'guest'|'email'|'federated_group'|'group'|'federated_team'|'team'|'federated_user'|'matrix'|'user', id: non-empty-lowercase-string}>
+	 * @since 36.0.0 Type 'matrix' is supported
 	 * @since 33.0.1 Parameter $supportMarkdown was added to decide if mentions inside markdown code blocks should be ignored (default to true)
 	 * @since 30.0.2 Type 'email' is supported
 	 * @since 29.0.0 Types 'federated_group', 'federated_team', 'team' and 'federated_user' are supported
@@ -213,7 +214,7 @@ public function getMentions(bool $supportMarkdown = true): array {
 			$message = preg_replace('/`[^`\n]*`/', '', $message);
 		}
 
-		$ok = preg_match_all("/\B(?<![^a-z0-9_\-@\.\'\s])@(\"(guest|email)\/[a-f0-9]+\"|\"(?:federated_)?(?:group|team|user){1}\/[a-z0-9_\-@\.\' \/:]+\"|\"[a-z0-9_\-@\.\' ]+\"|[a-z0-9_\-@\.\']+)/i", $message, $mentions);
+		$ok = preg_match_all("/\B(?<![^a-z0-9_\-@\.\'\s])@(\"(guest|email)\/[a-f0-9]+\"|\"(?:federated_)?(?:group|team|user){1}\/[a-z0-9_\-@\.\' \/:]+\"|\"matrix\/@[a-z0-9_\-\.=\/+]+:[a-z0-9\-\.:\[\]]+\"|\"[a-z0-9_\-@\.\' ]+\"|[a-z0-9_\-@\.\']+)/i", $message, $mentions);
 		if (!$ok || !isset($mentions[0])) {
 			return [];
 		}
@@ -253,6 +254,10 @@ public function getMentions(bool $supportMarkdown = true): array {
 				/** @var non-empty-lowercase-string $cleanId */
 				$cleanId = substr($cleanId, 15);
 				$result[] = ['type' => 'federated_user', 'id' => $cleanId];
+			} elseif (str_starts_with($cleanId, 'matrix/')) {
+				/** @var non-empty-lowercase-string $cleanId */
+				$cleanId = substr($cleanId, 7);
+				$result[] = ['type' => 'matrix', 'id' => $cleanId];
 			} else {
 				$result[] = ['type' => 'user', 'id' => $cleanId];
 			}
diff --git a/lib/public/Comments/IComment.php b/lib/public/Comments/IComment.php
index be43ace5df25d..8decb76d56fc6 100644
--- a/lib/public/Comments/IComment.php
+++ b/lib/public/Comments/IComment.php
@@ -127,7 +127,8 @@ public function setMessage($message, $maxLength = self::MAX_MESSAGE_LENGTH);
 	 *
 	 * @param bool $supportMarkdown
 	 * @return array each mention provides a 'type' and an 'id', see example below
-	 * @psalm-return list<array{type: 'guest'|'email'|'federated_group'|'group'|'federated_team'|'team'|'federated_user'|'user', id: non-empty-lowercase-string}>
+	 * @psalm-return list<array{type: 'guest'|'email'|'federated_group'|'group'|'federated_team'|'team'|'federated_user'|'matrix'|'user', id: non-empty-lowercase-string}>
+	 * @since 36.0.0 Type 'matrix' is supported
 	 * @since 33.0.1 Parameter $supportMarkdown was added to decide if mentions inside markdown code blocks should be ignored (default to true)
 	 * @since 30.0.2 Type 'email' is supported
 	 * @since 29.0.0 Types 'federated_group', 'federated_team', 'team' and 'federated_user' are supported
diff --git a/tests/lib/Comments/CommentTest.php b/tests/lib/Comments/CommentTest.php
index 011ae43ccfb78..26f0c8f4020f5 100644
--- a/tests/lib/Comments/CommentTest.php
+++ b/tests/lib/Comments/CommentTest.php
@@ -251,6 +251,10 @@ public static function mentionsProvider(): array {
 				"Mention @alice but not in unclosed tilde code block\n~~~\n@bob",
 				[['type' => 'user', 'id' => 'alice']],
 			],
+			[
+				'Matrix users @"matrix/@bob:example.org" and @"matrix/@carol.c=1/x+y:[2001:db8::1]:8448" but not @"matrix/@dave" or @"matrix/eve:example.org"',
+				[['type' => 'matrix', 'id' => '@carol.c=1/x+y:[2001:db8::1]:8448'], ['type' => 'matrix', 'id' => '@bob:example.org']],
+			],
 		];
 	}