diff --git a/config/set/php83.php b/config/set/php83.php
index 91a264d0c02..1a4e76d912f 100644
--- a/config/set/php83.php
+++ b/config/set/php83.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
+use Rector\Php83\Rector\Class_\ReadOnlyAnonymousClassRector;
 use Rector\Php83\Rector\ClassConst\AddTypeToConstRector;
 use Rector\Php83\Rector\ClassMethod\AddOverrideAttributeToOverriddenMethodsRector;
 use Rector\Php83\Rector\FuncCall\CombineHostPortLdapUriRector;
@@ -14,5 +15,6 @@
         AddTypeToConstRector::class,
         CombineHostPortLdapUriRector::class,
         RemoveGetClassGetParentClassNoArgsRector::class,
+        ReadOnlyAnonymousClassRector::class,
     ]);
 };
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/extends_readonly_class.php.inc b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/extends_readonly_class.php.inc
new file mode 100644
index 00000000000..c86363ef8ed
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/extends_readonly_class.php.inc
@@ -0,0 +1,25 @@
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+use Rector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Source\ParentAlreadyReadonly;
+
+new class() extends ParentAlreadyReadonly
+{
+   private readonly string $name = 'test';
+};
+
+?>
+-----
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+use Rector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Source\ParentAlreadyReadonly;
+
+new readonly class() extends ParentAlreadyReadonly
+{
+   private string $name = 'test';
+};
+
+?>
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/parenthesized_with_anonymous_class.php.inc b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/parenthesized_with_anonymous_class.php.inc
new file mode 100644
index 00000000000..a48d4a474ec
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/parenthesized_with_anonymous_class.php.inc
@@ -0,0 +1,21 @@
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+(new class()
+{
+   private readonly string $name = 'test';
+});
+
+?>
+-----
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+(new readonly class()
+{
+   private string $name = 'test';
+});
+
+?>
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/skip_named_class.php.inc b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/skip_named_class.php.inc
new file mode 100644
index 00000000000..78913fb7b1b
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/skip_named_class.php.inc
@@ -0,0 +1,8 @@
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+class SkipNamedClass
+{
+   private readonly string $name = 'test';
+}
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/with_anonymous_class.php.inc b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/with_anonymous_class.php.inc
new file mode 100644
index 00000000000..51914e275b2
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Fixture/with_anonymous_class.php.inc
@@ -0,0 +1,21 @@
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+new class()
+{
+   private readonly string $name = 'test';
+};
+
+?>
+-----
+<?php
+
+namespace newRector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Fixture;
+
+new readonly class()
+{
+   private string $name = 'test';
+};
+
+?>
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/ReadOnlyAnonymousClassRectorTest.php b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/ReadOnlyAnonymousClassRectorTest.php
new file mode 100644
index 00000000000..90e50cff133
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/ReadOnlyAnonymousClassRectorTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class ReadOnlyAnonymousClassRectorTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Source/ParentAlreadyReadonly.php b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Source/ParentAlreadyReadonly.php
new file mode 100644
index 00000000000..1d2d28d9d1a
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/Source/ParentAlreadyReadonly.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\Source;
+
+readonly abstract class ParentAlreadyReadonly
+{
+}
diff --git a/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/config/configured_rule.php b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/config/configured_rule.php
new file mode 100644
index 00000000000..d07e632bb60
--- /dev/null
+++ b/rules-tests/Php83/Rector/Class_/ReadOnlyAnonymousClassRector/config/configured_rule.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\Php83\Rector\Class_\ReadOnlyAnonymousClassRector;
+use Rector\ValueObject\PhpVersionFeature;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ReadOnlyAnonymousClassRector::class);
+
+    $rectorConfig->phpVersion(PhpVersionFeature::READONLY_ANONYMOUS_CLASS);
+};
diff --git a/rules/Php82/NodeManipulator/ReadonlyClassManipulator.php b/rules/Php82/NodeManipulator/ReadonlyClassManipulator.php
new file mode 100644
index 00000000000..b28f3b74a2b
--- /dev/null
+++ b/rules/Php82/NodeManipulator/ReadonlyClassManipulator.php
@@ -0,0 +1,251 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php82\NodeManipulator;
+
+use PhpParser\Node\Name\FullyQualified;
+use PhpParser\Node\Param;
+use PhpParser\Node\Stmt\Class_;
+use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Property;
+use PHPStan\Analyser\Scope;
+use PHPStan\BetterReflection\Reflection\Adapter\ReflectionProperty;
+use PHPStan\Reflection\ClassReflection;
+use PHPStan\Reflection\ReflectionProvider;
+use Rector\Php80\NodeAnalyzer\PhpAttributeAnalyzer;
+use Rector\Php81\Enum\AttributeName;
+use Rector\Php81\NodeManipulator\AttributeGroupNewLiner;
+use Rector\PHPStan\ScopeFetcher;
+use Rector\Privatization\NodeManipulator\VisibilityManipulator;
+use Rector\ValueObject\Application\File;
+use Rector\ValueObject\MethodName;
+use Rector\ValueObject\Visibility;
+
+final readonly class ReadonlyClassManipulator
+{
+    public function __construct(
+        private VisibilityManipulator $visibilityManipulator,
+        private PhpAttributeAnalyzer $phpAttributeAnalyzer,
+        private ReflectionProvider $reflectionProvider,
+        private AttributeGroupNewLiner $attributeGroupNewLiner
+    ) {
+    }
+
+    public function process(Class_ $class, File $file): Class_|null
+    {
+        $scope = ScopeFetcher::fetch($class);
+        if ($this->shouldSkip($class, $scope)) {
+            return null;
+        }
+
+        $this->visibilityManipulator->makeReadonly($class);
+
+        $constructClassMethod = $class->getMethod(MethodName::CONSTRUCT);
+
+        if ($constructClassMethod instanceof ClassMethod) {
+            foreach ($constructClassMethod->getParams() as $param) {
+                $this->visibilityManipulator->removeReadonly($param);
+
+                if ($param->attrGroups !== []) {
+                    $this->attributeGroupNewLiner->newLine($file, $param);
+                }
+            }
+        }
+
+        foreach ($class->getProperties() as $property) {
+            $this->visibilityManipulator->removeReadonly($property);
+
+            if ($property->attrGroups !== []) {
+                $this->attributeGroupNewLiner->newLine($file, $property);
+            }
+        }
+
+        if ($class->attrGroups !== []) {
+            $this->attributeGroupNewLiner->newLine($file, $class);
+        }
+
+        return $class;
+    }
+
+    /**
+     * @return ClassReflection[]
+     */
+    private function resolveParentClassReflections(Scope $scope): array
+    {
+        $classReflection = $scope->getClassReflection();
+        if (! $classReflection instanceof ClassReflection) {
+            return [];
+        }
+
+        return $classReflection->getParents();
+    }
+
+    /**
+     * @param Property[] $properties
+     */
+    private function hasNonTypedProperty(array $properties): bool
+    {
+        foreach ($properties as $property) {
+            // properties of readonly class must always have type
+            if ($property->type === null) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private function shouldSkip(Class_ $class, Scope $scope): bool
+    {
+        $classReflection = $scope->getClassReflection();
+        if (! $classReflection instanceof ClassReflection) {
+            return true;
+        }
+
+        if ($this->shouldSkipClass($class)) {
+            return true;
+        }
+
+        $parents = $this->resolveParentClassReflections($scope);
+
+        if (! $class->isAnonymous() && ! $class->isFinal()) {
+            return ! $this->isExtendsReadonlyClass($parents);
+        }
+
+        foreach ($parents as $parent) {
+            if (! $parent->isReadOnly()) {
+                return true;
+            }
+        }
+
+        $properties = $class->getProperties();
+        if ($this->hasWritableProperty($properties)) {
+            return true;
+        }
+
+        if ($this->hasNonTypedProperty($properties)) {
+            return true;
+        }
+
+        if ($this->shouldSkipConsumeTraitProperty($class)) {
+            return true;
+        }
+
+        $constructClassMethod = $class->getMethod(MethodName::CONSTRUCT);
+        if (! $constructClassMethod instanceof ClassMethod) {
+            // no __construct means no property promotion, skip if class has no property defined
+            return $properties === [];
+        }
+
+        $params = $constructClassMethod->getParams();
+        if ($params === []) {
+            // no params means no property promotion, skip if class has no property defined
+            return $properties === [];
+        }
+
+        return $this->shouldSkipParams($params);
+    }
+
+    private function shouldSkipConsumeTraitProperty(Class_ $class): bool
+    {
+        $traitUses = $class->getTraitUses();
+        foreach ($traitUses as $traitUse) {
+            foreach ($traitUse->traits as $trait) {
+                $traitName = $trait->toString();
+
+                // trait not autoloaded
+                if (! $this->reflectionProvider->hasClass($traitName)) {
+                    return true;
+                }
+
+                $traitClassReflection = $this->reflectionProvider->getClass($traitName);
+                $nativeReflection = $traitClassReflection->getNativeReflection();
+
+                if ($this->hasReadonlyProperty($nativeReflection->getProperties())) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param ReflectionProperty[] $properties
+     */
+    private function hasReadonlyProperty(array $properties): bool
+    {
+        foreach ($properties as $property) {
+            if (! $property->isReadOnly()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param ClassReflection[] $parents
+     */
+    private function isExtendsReadonlyClass(array $parents): bool
+    {
+        foreach ($parents as $parent) {
+            if ($parent->isReadOnly()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param Property[] $properties
+     */
+    private function hasWritableProperty(array $properties): bool
+    {
+        foreach ($properties as $property) {
+            if (! $property->isReadonly()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private function shouldSkipClass(Class_ $class): bool
+    {
+        // need to have test fixture once feature added to  nikic/PHP-Parser
+        if ($this->visibilityManipulator->hasVisibility($class, Visibility::READONLY)) {
+            return true;
+        }
+
+        if ($this->phpAttributeAnalyzer->hasPhpAttribute($class, AttributeName::ALLOW_DYNAMIC_PROPERTIES)) {
+            return true;
+        }
+
+        return $class->extends instanceof FullyQualified && ! $this->reflectionProvider->hasClass(
+            $class->extends->toString()
+        );
+    }
+
+    /**
+     * @param Param[] $params
+     */
+    private function shouldSkipParams(array $params): bool
+    {
+        foreach ($params as $param) {
+            // has non-readonly property promotion
+            if (! $this->visibilityManipulator->hasVisibility($param, Visibility::READONLY) && $param->isPromoted()) {
+                return true;
+            }
+
+            // type is missing, invalid syntax
+            if ($param->type === null) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
diff --git a/rules/Php82/Rector/Class_/ReadOnlyClassRector.php b/rules/Php82/Rector/Class_/ReadOnlyClassRector.php
index eeb479b1702..41b58be53a7 100644
--- a/rules/Php82/Rector/Class_/ReadOnlyClassRector.php
+++ b/rules/Php82/Rector/Class_/ReadOnlyClassRector.php
@@ -5,25 +5,10 @@
 namespace Rector\Php82\Rector\Class_;
 
 use PhpParser\Node;
-use PhpParser\Node\Name\FullyQualified;
-use PhpParser\Node\Param;
 use PhpParser\Node\Stmt\Class_;
-use PhpParser\Node\Stmt\ClassMethod;
-use PhpParser\Node\Stmt\Property;
-use PHPStan\Analyser\Scope;
-use PHPStan\BetterReflection\Reflection\Adapter\ReflectionProperty;
-use PHPStan\Reflection\ClassReflection;
-use PHPStan\Reflection\ReflectionProvider;
-use Rector\NodeAnalyzer\ClassAnalyzer;
-use Rector\Php80\NodeAnalyzer\PhpAttributeAnalyzer;
-use Rector\Php81\Enum\AttributeName;
-use Rector\Php81\NodeManipulator\AttributeGroupNewLiner;
-use Rector\PHPStan\ScopeFetcher;
-use Rector\Privatization\NodeManipulator\VisibilityManipulator;
+use Rector\Php82\NodeManipulator\ReadonlyClassManipulator;
 use Rector\Rector\AbstractRector;
-use Rector\ValueObject\MethodName;
 use Rector\ValueObject\PhpVersionFeature;
-use Rector\ValueObject\Visibility;
 use Rector\VersionBonding\Contract\MinPhpVersionInterface;
 use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
 use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
@@ -34,11 +19,7 @@
 final class ReadOnlyClassRector extends AbstractRector implements MinPhpVersionInterface
 {
     public function __construct(
-        private readonly ClassAnalyzer $classAnalyzer,
-        private readonly VisibilityManipulator $visibilityManipulator,
-        private readonly PhpAttributeAnalyzer $phpAttributeAnalyzer,
-        private readonly ReflectionProvider $reflectionProvider,
-        private readonly AttributeGroupNewLiner $attributeGroupNewLiner
+        private readonly ReadonlyClassManipulator $readonlyClassManipulator
     ) {
     }
 
@@ -83,226 +64,15 @@ public function getNodeTypes(): array
      */
     public function refactor(Node $node): ?Node
     {
-        $scope = ScopeFetcher::fetch($node);
-        if ($this->shouldSkip($node, $scope)) {
+        if ($node->isAnonymous()) {
             return null;
         }
 
-        $this->visibilityManipulator->makeReadonly($node);
-
-        $constructClassMethod = $node->getMethod(MethodName::CONSTRUCT);
-
-        if ($constructClassMethod instanceof ClassMethod) {
-            foreach ($constructClassMethod->getParams() as $param) {
-                $this->visibilityManipulator->removeReadonly($param);
-
-                if ($param->attrGroups !== []) {
-                    $this->attributeGroupNewLiner->newLine($this->file, $param);
-                }
-            }
-        }
-
-        foreach ($node->getProperties() as $property) {
-            $this->visibilityManipulator->removeReadonly($property);
-
-            if ($property->attrGroups !== []) {
-                $this->attributeGroupNewLiner->newLine($this->file, $property);
-            }
-        }
-
-        if ($node->attrGroups !== []) {
-            $this->attributeGroupNewLiner->newLine($this->file, $node);
-        }
-
-        return $node;
+        return $this->readonlyClassManipulator->process($node, $this->file);
     }
 
     public function provideMinPhpVersion(): int
     {
         return PhpVersionFeature::READONLY_CLASS;
     }
-
-    /**
-     * @return ClassReflection[]
-     */
-    private function resolveParentClassReflections(Scope $scope): array
-    {
-        $classReflection = $scope->getClassReflection();
-        if (! $classReflection instanceof ClassReflection) {
-            return [];
-        }
-
-        return $classReflection->getParents();
-    }
-
-    /**
-     * @param Property[] $properties
-     */
-    private function hasNonTypedProperty(array $properties): bool
-    {
-        foreach ($properties as $property) {
-            // properties of readonly class must always have type
-            if ($property->type === null) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    private function shouldSkip(Class_ $class, Scope $scope): bool
-    {
-        $classReflection = $scope->getClassReflection();
-        if (! $classReflection instanceof ClassReflection) {
-            return true;
-        }
-
-        if ($this->shouldSkipClass($class)) {
-            return true;
-        }
-
-        $parents = $this->resolveParentClassReflections($scope);
-        if (! $class->isFinal()) {
-            return ! $this->isExtendsReadonlyClass($parents);
-        }
-
-        foreach ($parents as $parent) {
-            if (! $parent->isReadOnly()) {
-                return true;
-            }
-        }
-
-        $properties = $class->getProperties();
-        if ($this->hasWritableProperty($properties)) {
-            return true;
-        }
-
-        if ($this->hasNonTypedProperty($properties)) {
-            return true;
-        }
-
-        if ($this->shouldSkipConsumeTraitProperty($class)) {
-            return true;
-        }
-
-        $constructClassMethod = $class->getMethod(MethodName::CONSTRUCT);
-        if (! $constructClassMethod instanceof ClassMethod) {
-            // no __construct means no property promotion, skip if class has no property defined
-            return $properties === [];
-        }
-
-        $params = $constructClassMethod->getParams();
-        if ($params === []) {
-            // no params means no property promotion, skip if class has no property defined
-            return $properties === [];
-        }
-
-        return $this->shouldSkipParams($params);
-    }
-
-    private function shouldSkipConsumeTraitProperty(Class_ $class): bool
-    {
-        $traitUses = $class->getTraitUses();
-        foreach ($traitUses as $traitUse) {
-            foreach ($traitUse->traits as $trait) {
-                $traitName = $trait->toString();
-
-                // trait not autoloaded
-                if (! $this->reflectionProvider->hasClass($traitName)) {
-                    return true;
-                }
-
-                $traitClassReflection = $this->reflectionProvider->getClass($traitName);
-                $nativeReflection = $traitClassReflection->getNativeReflection();
-
-                if ($this->hasReadonlyProperty($nativeReflection->getProperties())) {
-                    return true;
-                }
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * @param ReflectionProperty[] $properties
-     */
-    private function hasReadonlyProperty(array $properties): bool
-    {
-        foreach ($properties as $property) {
-            if (! $property->isReadOnly()) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * @param ClassReflection[] $parents
-     */
-    private function isExtendsReadonlyClass(array $parents): bool
-    {
-        foreach ($parents as $parent) {
-            if ($parent->isReadOnly()) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    /**
-     * @param Property[] $properties
-     */
-    private function hasWritableProperty(array $properties): bool
-    {
-        foreach ($properties as $property) {
-            if (! $property->isReadonly()) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    private function shouldSkipClass(Class_ $class): bool
-    {
-        // need to have test fixture once feature added to  nikic/PHP-Parser
-        if ($this->visibilityManipulator->hasVisibility($class, Visibility::READONLY)) {
-            return true;
-        }
-
-        if ($this->classAnalyzer->isAnonymousClass($class)) {
-            return true;
-        }
-
-        if ($this->phpAttributeAnalyzer->hasPhpAttribute($class, AttributeName::ALLOW_DYNAMIC_PROPERTIES)) {
-            return true;
-        }
-
-        return $class->extends instanceof FullyQualified && ! $this->reflectionProvider->hasClass(
-            $class->extends->toString()
-        );
-    }
-
-    /**
-     * @param Param[] $params
-     */
-    private function shouldSkipParams(array $params): bool
-    {
-        foreach ($params as $param) {
-            // has non-readonly property promotion
-            if (! $this->visibilityManipulator->hasVisibility($param, Visibility::READONLY) && $param->isPromoted()) {
-                return true;
-            }
-
-            // type is missing, invalid syntax
-            if ($param->type === null) {
-                return true;
-            }
-        }
-
-        return false;
-    }
 }
diff --git a/rules/Php83/Rector/Class_/ReadOnlyAnonymousClassRector.php b/rules/Php83/Rector/Class_/ReadOnlyAnonymousClassRector.php
new file mode 100644
index 00000000000..aaf2febd523
--- /dev/null
+++ b/rules/Php83/Rector/Class_/ReadOnlyAnonymousClassRector.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php83\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\Class_;
+use Rector\Php82\NodeManipulator\ReadonlyClassManipulator;
+use Rector\Rector\AbstractRector;
+use Rector\ValueObject\PhpVersionFeature;
+use Rector\VersionBonding\Contract\MinPhpVersionInterface;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\Php83\Rector\Class_\ReadOnlyAnonymousClassRector\ReadOnlyAnonymousClassRectorTest
+ */
+final class ReadOnlyAnonymousClassRector extends AbstractRector implements MinPhpVersionInterface
+{
+    public function __construct(
+        private readonly ReadonlyClassManipulator $readonlyClassManipulator
+    ) {
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition('Decorate read-only anonymous class with `readonly` attribute', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+new class
+{
+    public function __construct(
+        private readonly string $name
+    ) {
+    }
+};
+CODE_SAMPLE
+
+                ,
+                <<<'CODE_SAMPLE'
+new readonly class
+{
+    public function __construct(
+        private string $name
+    ) {
+    }
+};
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if (! $node->isAnonymous()) {
+            return null;
+        }
+
+        return $this->readonlyClassManipulator->process($node, $this->file);
+    }
+
+    public function provideMinPhpVersion(): int
+    {
+        return PhpVersionFeature::READONLY_CLASS;
+    }
+}
diff --git a/rules/Privatization/NodeManipulator/VisibilityManipulator.php b/rules/Privatization/NodeManipulator/VisibilityManipulator.php
index c1b8c93d292..6f27f9bab7f 100644
--- a/rules/Privatization/NodeManipulator/VisibilityManipulator.php
+++ b/rules/Privatization/NodeManipulator/VisibilityManipulator.php
@@ -5,6 +5,7 @@
 namespace Rector\Privatization\NodeManipulator;
 
 use PhpParser\Modifiers;
+use PhpParser\Node\Expr\New_;
 use PhpParser\Node\Param;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\ClassConst;
@@ -128,11 +129,15 @@ public function isReadonly(Class_ | Property | Param $node): bool
         return $this->hasVisibility($node, Visibility::READONLY);
     }
 
-    public function removeReadonly(Class_ | Property | Param $node): void
+    public function removeReadonly(Class_ | Property | Param | New_ $node): void
     {
         $isConstructorPromotionBefore = $node instanceof Param && $node->isPromoted();
 
-        $node->flags &= ~Modifiers::READONLY;
+        if (! $node instanceof New_) {
+            $node->flags &= ~Modifiers::READONLY;
+        } elseif ($node->class instanceof Class_) {
+            $node->class->flags &= ~Modifiers::READONLY;
+        }
 
         $isConstructorPromotionAfter = $node instanceof Param && $node->isPromoted();
 
diff --git a/src/PhpParser/Printer/BetterStandardPrinter.php b/src/PhpParser/Printer/BetterStandardPrinter.php
index d178d15deb4..74e2ad19bd2 100644
--- a/src/PhpParser/Printer/BetterStandardPrinter.php
+++ b/src/PhpParser/Printer/BetterStandardPrinter.php
@@ -18,6 +18,7 @@
 use PhpParser\Node\Expr\Instanceof_;
 use PhpParser\Node\Expr\Match_;
 use PhpParser\Node\Expr\MethodCall;
+use PhpParser\Node\Expr\New_;
 use PhpParser\Node\Expr\Ternary;
 use PhpParser\Node\Expr\Yield_;
 use PhpParser\Node\InterpolatedStringPart;
@@ -30,6 +31,7 @@
 use PhpParser\Node\Stmt\InlineHTML;
 use PhpParser\Node\Stmt\Nop;
 use PhpParser\PrettyPrinter\Standard;
+use PHPStan\Node\AnonymousClassNode;
 use PHPStan\Node\Expr\AlwaysRememberedExpr;
 use Rector\Configuration\Option;
 use Rector\Configuration\Parameter\SimpleParameterProvider;
@@ -149,6 +151,10 @@ protected function p(
 
         $content = parent::p($node, $precedence, $lhsPrecedence, $parentFormatPreserved);
 
+        if ($node instanceof New_ && $node->class instanceof AnonymousClassNode) {
+            $content = 'new ' . ltrim($content, 'new ');
+        }
+
         return $node->getAttribute(AttributeKey::WRAPPED_IN_PARENTHESES) === true
             ? ('(' . $content . ')')
             : $content;
diff --git a/src/ValueObject/PhpVersionFeature.php b/src/ValueObject/PhpVersionFeature.php
index 12e1fea62dd..80c18b6e03f 100644
--- a/src/ValueObject/PhpVersionFeature.php
+++ b/src/ValueObject/PhpVersionFeature.php
@@ -629,6 +629,12 @@ final class PhpVersionFeature
      */
     public const READONLY_CLASS = PhpVersion::PHP_82;
 
+    /**
+     * @see https://www.php.net/manual/en/migration83.new-features.php#migration83.new-features.core.readonly-modifier-improvements
+     * @var int
+     */
+    public const READONLY_ANONYMOUS_CLASS = PhpVersion::PHP_83;
+
     /**
      * @see https://wiki.php.net/rfc/mixed_type_v2
      * @var int