diff --git a/.psalm/baseline.xml b/.psalm/baseline.xml
index a1c98407ac5..a941c899ce9 100644
--- a/.psalm/baseline.xml
+++ b/.psalm/baseline.xml
@@ -640,13 +640,6 @@
     </RedundantCondition>
   </file>
   <file src="src/Metadata/Api/Groups.php">
-    <LessSpecificReturnStatement>
-      <code><![CDATA[array_unique($groups)]]></code>
-      <code><![CDATA[array_unique($groups)]]></code>
-    </LessSpecificReturnStatement>
-    <MoreSpecificReturnType>
-      <code><![CDATA[list<string>]]></code>
-    </MoreSpecificReturnType>
     <RedundantCondition>
       <code><![CDATA[$metadata instanceof CoversFunction]]></code>
       <code><![CDATA[$metadata instanceof UsesFunction]]></code>
diff --git a/src/Metadata/Api/Groups.php b/src/Metadata/Api/Groups.php
index 73341851a4b..5c78cbdc340 100644
--- a/src/Metadata/Api/Groups.php
+++ b/src/Metadata/Api/Groups.php
@@ -10,6 +10,7 @@
 namespace PHPUnit\Metadata\Api;
 
 use function array_flip;
+use function array_key_exists;
 use function array_unique;
 use function assert;
 use function strtolower;
@@ -29,14 +30,25 @@
  */
 final class Groups
 {
+    /**
+     * @var array<string, array<int, string>>
+     */
+    private static array $groupCache = [];
+
     /**
      * @psalm-param class-string $className
      * @psalm-param non-empty-string $methodName
      *
-     * @psalm-return list<string>
+     * @psalm-return array<int, string>
      */
     public function groups(string $className, string $methodName, bool $includeVirtual = true): array
     {
+        $key = $className . '::' . $methodName . '::' . $includeVirtual;
+
+        if (array_key_exists($key, self::$groupCache)) {
+            return self::$groupCache[$key];
+        }
+
         $groups = [];
 
         foreach (Registry::parser()->forClassAndMethod($className, $methodName)->isGroup() as $group) {
@@ -50,7 +62,7 @@ public function groups(string $className, string $methodName, bool $includeVirtu
         }
 
         if (!$includeVirtual) {
-            return array_unique($groups);
+            return self::$groupCache[$key] = array_unique($groups);
         }
 
         foreach (Registry::parser()->forClassAndMethod($className, $methodName) as $metadata) {
@@ -85,7 +97,7 @@ public function groups(string $className, string $methodName, bool $includeVirtu
             }
         }
 
-        return array_unique($groups);
+        return self::$groupCache[$key] = array_unique($groups);
     }
 
     /**