diff --git a/config/set/php/php80.yaml b/config/set/php/php80.yaml
index 9c954f19c8f..48908e8f551 100644
--- a/config/set/php/php80.yaml
+++ b/config/set/php/php80.yaml
@@ -3,3 +3,4 @@ services:
     Rector\Php80\Rector\NotIdentical\StrContainsRector: null
     Rector\Php80\Rector\Identical\StrStartsWithRector: null
     Rector\Php80\Rector\Identical\StrEndsWithRector: null
+    Rector\Php80\Rector\Class_\StringableForToStringRector: null
diff --git a/docs/AllRectorsOverview.md b/docs/AllRectorsOverview.md
index 5abb5d6144c..38faff3a76c 100644
--- a/docs/AllRectorsOverview.md
+++ b/docs/AllRectorsOverview.md
@@ -1,4 +1,4 @@
-# All 501 Rectors Overview
+# All 502 Rectors Overview
 
 - [Projects](#projects)
 - [General](#general)
@@ -7915,6 +7915,27 @@ Change helper functions to str_starts_with()
 
 <br>
 
+### `StringableForToStringRector`
+
+- class: [`Rector\Php80\Rector\Class_\StringableForToStringRector`](/../master/rules/php80/src/Rector/Class_/StringableForToStringRector.php)
+- [test fixtures](/../master/rules/php80/tests/Rector/Class_/StringableForToStringRector/Fixture)
+
+Add `Stringable` interface to classes with `__toString()` method
+
+```diff
+-class SomeClass
++class SomeClass implements Stringable
+ {
+-    public function __toString()
++    public function __toString(): string
+     {
+         return 'I can stringz';
+     }
+ }
+```
+
+<br>
+
 ### `UnionTypesRector`
 
 - class: [`Rector\Php80\Rector\FunctionLike\UnionTypesRector`](/../master/rules/php80/src/Rector/FunctionLike/UnionTypesRector.php)
diff --git a/rules/php80/src/Rector/Class_/StringableForToStringRector.php b/rules/php80/src/Rector/Class_/StringableForToStringRector.php
new file mode 100644
index 00000000000..889deea5edc
--- /dev/null
+++ b/rules/php80/src/Rector/Class_/StringableForToStringRector.php
@@ -0,0 +1,99 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Name;
+use PhpParser\Node\Name\FullyQualified;
+use PhpParser\Node\Stmt\Class_;
+use Rector\Core\PhpParser\Node\Manipulator\ClassManipulator;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Core\RectorDefinition\CodeSample;
+use Rector\Core\RectorDefinition\RectorDefinition;
+
+/**
+ * @see https://wiki.php.net/rfc/stringable
+ *
+ * @see \Rector\Php80\Tests\Rector\Class_\StringableForToStringRector\StringableForToStringRectorTest
+ */
+final class StringableForToStringRector extends AbstractRector
+{
+    /**
+     * @var string
+     */
+    private const STRINGABLE = 'Stringable';
+
+    /**
+     * @var ClassManipulator
+     */
+    private $classManipulator;
+
+    public function __construct(ClassManipulator $classManipulator)
+    {
+        $this->classManipulator = $classManipulator;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Add `Stringable` interface to classes with `__toString()` method', [
+            new CodeSample(
+                <<<'PHP'
+class SomeClass
+{
+    public function __toString()
+    {
+        return 'I can stringz';
+    }
+}
+PHP
+,
+                <<<'PHP'
+class SomeClass implements Stringable
+{
+    public function __toString(): string
+    {
+        return 'I can stringz';
+    }
+}
+PHP
+
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $toStringClassMethod = $node->getMethod('__toString');
+        if ($toStringClassMethod === null) {
+            return null;
+        }
+
+        if ($this->classManipulator->hasInterface($node, self::STRINGABLE)) {
+            return null;
+        }
+
+        // add interface
+        $node->implements[] = new FullyQualified(self::STRINGABLE);
+
+        // add return type
+
+        if ($toStringClassMethod->returnType === null) {
+            $toStringClassMethod->returnType = new Name('string');
+        }
+
+        return $node;
+    }
+}
diff --git a/rules/php80/tests/Rector/Class_/StringableForToStringRector/Fixture/fixture.php.inc b/rules/php80/tests/Rector/Class_/StringableForToStringRector/Fixture/fixture.php.inc
new file mode 100644
index 00000000000..ae2495e6767
--- /dev/null
+++ b/rules/php80/tests/Rector/Class_/StringableForToStringRector/Fixture/fixture.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Php80\Tests\Rector\Class_\StringableForToStringRector\Fixture;
+
+class SomeClass
+{
+    public function __toString()
+    {
+        return 'I can stringz';
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Php80\Tests\Rector\Class_\StringableForToStringRector\Fixture;
+
+class SomeClass implements \Stringable
+{
+    public function __toString(): string
+    {
+        return 'I can stringz';
+    }
+}
+
+?>
diff --git a/rules/php80/tests/Rector/Class_/StringableForToStringRector/StringableForToStringRectorTest.php b/rules/php80/tests/Rector/Class_/StringableForToStringRector/StringableForToStringRectorTest.php
new file mode 100644
index 00000000000..8591e5c3013
--- /dev/null
+++ b/rules/php80/tests/Rector/Class_/StringableForToStringRector/StringableForToStringRectorTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Tests\Rector\Class_\StringableForToStringRector;
+
+use Iterator;
+use Rector\Core\Testing\PHPUnit\AbstractRectorTestCase;
+use Rector\Php80\Rector\Class_\StringableForToStringRector;
+
+final class StringableForToStringRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(string $file): void
+    {
+        $this->doTestFile($file);
+    }
+
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    protected function getRectorClass(): string
+    {
+        return StringableForToStringRector::class;
+    }
+}