diff --git a/bench/remove_unused_constructor_param_attribute_bench.php b/bench/remove_unused_constructor_param_attribute_bench.php
new file mode 100644
index 00000000000..d73632e5977
--- /dev/null
+++ b/bench/remove_unused_constructor_param_attribute_bench.php
@@ -0,0 +1,98 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Benchmark for RemoveUnusedConstructorParamRector.
+ *
+ * The rule subscribes to Class_. To skip attribute marker classes (whose constructor params are
+ * meta, not dead code) it resolved the class reflection and called ClassReflection::isAttributeClass().
+ * Whether a class carries #[Attribute] is declared directly on the class, so it is fully visible in
+ * the node's attrGroups - no reflection needed.
+ *
+ * The change reads it off the node (isAttributeClass(Class_)) and runs that check BEFORE
+ * resolveClassReflection(). An attribute marker class with a doc-commented constructor now bails
+ * before any reflection resolves.
+ *
+ * This bench parses a file of many attribute marker classes, each with a doc-commented constructor
+ * holding an unused param, attaches scope (as the real run does), then drives refactor() over every
+ * Class_ node. Each node hits the attribute skip and never changes, so the calls are repeatable.
+ *
+ * Run on both branches to compare:
+ *   php bench/remove_unused_constructor_param_attribute_bench.php
+ *
+ * Reports CPU time (user+sys) and wall time; CPU is the reliable metric, wall is noisy under
+ * concurrent load.
+ */
+
+use PhpParser\Node\Stmt\Class_;
+use Rector\DeadCode\Rector\ClassMethod\RemoveUnusedConstructorParamRector;
+use Rector\DependencyInjection\LazyContainerFactory;
+use Rector\PhpParser\Node\BetterNodeFinder;
+use Rector\Testing\TestingParser\TestingParser;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+const MARKERS = 150; // attribute marker classes with a doc-commented constructor
+const REPEAT = 60;   // outer repeats over the whole class set
+
+$rectorConfig = (new LazyContainerFactory())->create();
+$rectorConfig->boot();
+
+/** @var TestingParser $testingParser */
+$testingParser = $rectorConfig->make(TestingParser::class);
+
+/** @var BetterNodeFinder $betterNodeFinder */
+$betterNodeFinder = $rectorConfig->make(BetterNodeFinder::class);
+
+$rector = $rectorConfig->make(RemoveUnusedConstructorParamRector::class);
+
+// generate a file of attribute marker classes, each with a doc-commented constructor whose param
+// looks unused - the rule must skip them because they are markers, not dead code
+$source = "<?php\n\nnamespace Bench;\n\n";
+for ($i = 0; $i < MARKERS; ++$i) {
+    $source .= "#[\\Attribute]\nfinal class Marker{$i}\n{\n";
+    $source .= "    /**\n     * @param string \$name\n     */\n";
+    $source .= "    public function __construct(string \$name)\n    {\n    }\n}\n\n";
+}
+
+$sourceFilePath = tempnam(sys_get_temp_dir(), 'bench_') . '.php';
+file_put_contents($sourceFilePath, $source);
+
+$stmts = $testingParser->parseFileToDecoratedNodes($sourceFilePath);
+
+/** @var Class_[] $classes */
+$classes = $betterNodeFinder->findInstanceOf($stmts, Class_::class);
+
+$cpuSeconds = static function (): float {
+    $usage = getrusage();
+    return $usage['ru_utime.tv_sec'] + $usage['ru_utime.tv_usec'] / 1_000_000
+        + $usage['ru_stime.tv_sec'] + $usage['ru_stime.tv_usec'] / 1_000_000;
+};
+
+$run = static function () use ($rector, $classes): void {
+    foreach ($classes as $class) {
+        $rector->refactor($class);
+    }
+};
+
+// warm up autoloading/reflection caches once, excluded from timing
+$run();
+
+$wallStart = microtime(true);
+$cpuStart = $cpuSeconds();
+
+for ($repeat = 0; $repeat < REPEAT; ++$repeat) {
+    $run();
+}
+
+$cpu = $cpuSeconds() - $cpuStart;
+$wall = microtime(true) - $wallStart;
+
+@unlink($sourceFilePath);
+
+$totalCalls = REPEAT * count($classes);
+
+printf('classes: %d, repeats: %d, refactor() calls: %d%s', count($classes), REPEAT, $totalCalls, PHP_EOL);
+printf('CPU:  %.4f s  (%.3f us/call)%s', $cpu, $cpu / $totalCalls * 1_000_000, PHP_EOL);
+printf('wall: %.4f s%s', $wall, PHP_EOL);
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector/Fixture/skip_imported_attribute_marker.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector/Fixture/skip_imported_attribute_marker.php.inc
new file mode 100644
index 00000000000..2bd81aa2000
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector/Fixture/skip_imported_attribute_marker.php.inc
@@ -0,0 +1,17 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedConstructorParamRector\Fixture;
+
+use Attribute;
+use Rector\Contract\Rector\RectorInterface;
+
+#[Attribute(Attribute::TARGET_CLASS)]
+final class SkipImportedAttributeMarker
+{
+    /**
+     * @param RectorInterface $someClass
+     */
+    public function __construct(string $someClass)
+    {
+    }
+}
diff --git a/rules/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector.php b/rules/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector.php
index 69e248c23ed..84ebda77784 100644
--- a/rules/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector.php
+++ b/rules/DeadCode/Rector/ClassMethod/RemoveUnusedConstructorParamRector.php
@@ -85,6 +85,11 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
+        // attribute marker classes keep constructor params; read straight off the node, no reflection
+        if ($this->isAttributeClass($node) && $constructorClassMethod->getDocComment() instanceof Doc) {
+            return null;
+        }
+
         $classReflection = $this->reflectionResolver->resolveClassReflection($node);
         if (! $classReflection instanceof ClassReflection) {
             return null;
@@ -98,11 +103,6 @@ public function refactor(Node $node): ?Node
             }
         }
 
-        // attributes can be used as markers
-        if ($classReflection->isAttributeClass() && $constructorClassMethod->getDocComment() instanceof Doc) {
-            return null;
-        }
-
         $changedConstructorClassMethod = $this->classMethodParamRemover->processRemoveParams($constructorClassMethod);
         if (! $changedConstructorClassMethod instanceof ClassMethod) {
             return null;
@@ -110,4 +110,17 @@ public function refactor(Node $node): ?Node
 
         return $node;
     }
+
+    private function isAttributeClass(Class_ $class): bool
+    {
+        foreach ($class->attrGroups as $attrGroup) {
+            foreach ($attrGroup->attrs as $attr) {
+                if ($this->isName($attr->name, 'Attribute')) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
 }