diff --git a/README.md b/README.md
index 2f75f9353..198b59d94 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ Slevomat Coding Standard for [PHP_CodeSniffer](https://github.com/PHPCSStandards
  - [SlevomatCodingStandard.Classes.DisallowStringExpressionPropertyFetch](doc/classes.md#slevomatcodingstandardclassesdisallowstringexpressionpropertyfetch-) 🔧
  - [SlevomatCodingStandard.Classes.EmptyLinesAroundClassBraces](doc/classes.md#slevomatcodingstandardclassesemptylinesaroundclassbraces-) 🔧
  - [SlevomatCodingStandard.Classes.EnumCaseSpacing](doc/classes.md#slevomatcodingstandardclassesenumcasespacing-) 🔧
+ - [SlevomatCodingStandard.Classes.ClassKeywordOrder](doc/classes.md#slevomatcodingstandardclassesclasskeywordorder-) 🔧
  - [SlevomatCodingStandard.Classes.ForbiddenPublicProperty](doc/classes.md#slevomatcodingstandardclassesforbiddenpublicproperty)
  - [SlevomatCodingStandard.Classes.MethodSpacing](doc/classes.md#slevomatcodingstandardclassesmethodspacing-) 🔧
  - [SlevomatCodingStandard.Classes.ModernClassNameReference](doc/classes.md#slevomatcodingstandardclassesmodernclassnamereference-) 🔧
diff --git a/SlevomatCodingStandard/Sniffs/Classes/ClassKeywordOrderSniff.php b/SlevomatCodingStandard/Sniffs/Classes/ClassKeywordOrderSniff.php
new file mode 100644
index 000000000..544ffc1a5
--- /dev/null
+++ b/SlevomatCodingStandard/Sniffs/Classes/ClassKeywordOrderSniff.php
@@ -0,0 +1,112 @@
+<?php declare(strict_types = 1);
+
+namespace SlevomatCodingStandard\Sniffs\Classes;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+use SlevomatCodingStandard\Helpers\TokenHelper;
+use function array_key_first;
+use function array_keys;
+use function array_map;
+use function array_values;
+use function count;
+use function implode;
+use function ksort;
+use function uasort;
+use const T_ABSTRACT;
+use const T_CLASS;
+use const T_FINAL;
+use const T_READONLY;
+use const T_WHITESPACE;
+
+class ClassKeywordOrderSniff implements Sniff
+{
+
+	public const CODE_WRONG_CLASS_KEYWORD_ORDER = 'WrongClassKeywordOrder';
+
+	/**
+	 * @return array<int, (int|string)>
+	 */
+	public function register(): array
+	{
+		return [
+			T_CLASS,
+		];
+	}
+
+	public function process(File $phpcsFile, int $stackPtr): void
+	{
+		$tokens = $phpcsFile->getTokens();
+
+		$modifierTokens = [
+			T_ABSTRACT => 'abstract',
+			T_FINAL => 'final',
+			T_READONLY => 'readonly',
+		];
+
+		$foundModifiers = [];
+		$currentIndex = TokenHelper::findPreviousEffective($phpcsFile, $stackPtr - 1);
+
+		while ($currentIndex !== null && isset($modifierTokens[$tokens[$currentIndex]['code']])) {
+			$foundModifiers[$currentIndex] = $tokens[$currentIndex]['code'];
+			$currentIndex = TokenHelper::findPreviousEffective($phpcsFile, $currentIndex - 1);
+		}
+
+		if (count($foundModifiers) === 0) {
+			return;
+		}
+
+		ksort($foundModifiers);
+
+		$actualOrderCodes = array_values($foundModifiers);
+		$actualOrderText = array_map(static fn ($code) => $modifierTokens[$code], $actualOrderCodes);
+
+		$sortedModifiers = $foundModifiers;
+		uasort($sortedModifiers, static function ($a, $b) {
+			$priority = [
+				T_ABSTRACT => 0,
+				T_FINAL => 0,
+				T_READONLY => 1,
+			];
+			return $priority[$a] <=> $priority[$b];
+		});
+
+		$expectedOrderCodes = array_values($sortedModifiers);
+		$expectedOrderText = array_map(static fn ($code) => $modifierTokens[$code], $expectedOrderCodes);
+
+		if ($actualOrderCodes === $expectedOrderCodes) {
+			return;
+		}
+
+		$error = 'Class keywords are not in the correct order. Found: "%s class"; Expected: "%s class"';
+		$data = [
+			implode(' ', $actualOrderText),
+			implode(' ', $expectedOrderText),
+		];
+
+		$fix = $phpcsFile->addFixableError($error, $stackPtr, self::CODE_WRONG_CLASS_KEYWORD_ORDER, $data);
+
+		if ($fix !== true) {
+			return;
+		}
+
+		$phpcsFile->fixer->beginChangeset();
+
+		foreach (array_keys($foundModifiers) as $ptr) {
+			$phpcsFile->fixer->replaceToken($ptr, '');
+
+			if ($tokens[$ptr + 1]['code'] === T_WHITESPACE) {
+				$phpcsFile->fixer->replaceToken($ptr + 1, '');
+			}
+		}
+
+		$firstModifierPtr = array_key_first($foundModifiers);
+
+		$newContent = implode(' ', $expectedOrderText) . ' ';
+
+		$phpcsFile->fixer->addContentBefore($firstModifierPtr, $newContent);
+
+		$phpcsFile->fixer->endChangeset();
+	}
+
+}
diff --git a/build/phpcs.xml b/build/phpcs.xml
index f7243821a..d6f415240 100644
--- a/build/phpcs.xml
+++ b/build/phpcs.xml
@@ -222,6 +222,7 @@
 	<rule ref="SlevomatCodingStandard.Classes.DisallowMultiPropertyDefinition"/>
 	<rule ref="SlevomatCodingStandard.Classes.EmptyLinesAroundClassBraces"/>
 	<rule ref="SlevomatCodingStandard.Classes.EnumCaseSpacing"/>
+	<rule ref="SlevomatCodingStandard.Classes.ClassKeywordOrder"/>
 	<rule ref="SlevomatCodingStandard.Classes.MethodSpacing"/>
 	<rule ref="SlevomatCodingStandard.Classes.ModernClassNameReference"/>
 	<rule ref="SlevomatCodingStandard.Classes.ParentCallSpacing"/>
diff --git a/doc/classes.md b/doc/classes.md
index a5688ccf4..eaa09abad 100644
--- a/doc/classes.md
+++ b/doc/classes.md
@@ -161,6 +161,12 @@ Sniff provides the following settings:
 * `minLinesCountBeforeWithoutComment`: minimum number of lines before enum case without a documentation comment or attribute
 * `maxLinesCountBeforeWithoutComment`: maximum number of lines before enum case without a documentation comment or attribute
 
+#### SlevomatCodingStandard.Classes.ClassKeywordOrder 🔧
+
+Enforces the correct order of class modifiers (e.g., `final`, `abstract`, `readonly`).
+
+Required order is (final | abstract) readonly class. That is, use either `final` or `abstract` (never both), then `readonly` if present, then `class`.
+
 #### SlevomatCodingStandard.Classes.ForbiddenPublicProperty
 
 Disallows using public properties.
diff --git a/tests/Sniffs/Classes/ClassKeywordOrderSniffTest.php b/tests/Sniffs/Classes/ClassKeywordOrderSniffTest.php
new file mode 100644
index 000000000..19e8c095c
--- /dev/null
+++ b/tests/Sniffs/Classes/ClassKeywordOrderSniffTest.php
@@ -0,0 +1,39 @@
+<?php declare(strict_types = 1);
+
+namespace SlevomatCodingStandard\Sniffs\Classes;
+
+use SlevomatCodingStandard\Sniffs\TestCase;
+
+class ClassKeywordOrderSniffTest extends TestCase
+{
+
+	public function testNoErrors(): void
+	{
+		$report = self::checkFile(__DIR__ . '/data/classKeywordOrderNoErrors.php');
+		self::assertNoSniffErrorInFile($report);
+	}
+
+	public function testErrors(): void
+	{
+		$report = self::checkFile(__DIR__ . '/data/classKeywordOrderErrors.php');
+
+		self::assertSame(2, $report->getErrorCount());
+
+		self::assertSniffError(
+			$report,
+			30,
+			ClassKeywordOrderSniff::CODE_WRONG_CLASS_KEYWORD_ORDER,
+			'Class keywords are not in the correct order. Found: "readonly final class"; Expected: "final readonly class"',
+		);
+
+		self::assertSniffError(
+			$report,
+			49,
+			ClassKeywordOrderSniff::CODE_WRONG_CLASS_KEYWORD_ORDER,
+			'Class keywords are not in the correct order. Found: "readonly abstract class"; Expected: "abstract readonly class"',
+		);
+
+		self::assertAllFixedInFile($report);
+	}
+
+}
diff --git a/tests/Sniffs/Classes/data/classKeywordOrderErrors.fixed.php b/tests/Sniffs/Classes/data/classKeywordOrderErrors.fixed.php
new file mode 100644
index 000000000..163ac1750
--- /dev/null
+++ b/tests/Sniffs/Classes/data/classKeywordOrderErrors.fixed.php
@@ -0,0 +1,56 @@
+<?php // lint >= 8.2
+
+class Foo1
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+final class Foo2
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+readonly class Foo3
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+final readonly class Foo4
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+
+abstract class Foo5
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+abstract readonly class Foo6
+{
+
+	public function bar()
+	{
+
+	}
+}
diff --git a/tests/Sniffs/Classes/data/classKeywordOrderErrors.php b/tests/Sniffs/Classes/data/classKeywordOrderErrors.php
new file mode 100644
index 000000000..b2cc0a46d
--- /dev/null
+++ b/tests/Sniffs/Classes/data/classKeywordOrderErrors.php
@@ -0,0 +1,56 @@
+<?php // lint >= 8.2
+
+class Foo1
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+final class Foo2
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+readonly class Foo3
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+readonly final class Foo4
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+
+abstract class Foo5
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+readonly abstract class Foo6
+{
+
+	public function bar()
+	{
+
+	}
+}
diff --git a/tests/Sniffs/Classes/data/classKeywordOrderNoErrors.php b/tests/Sniffs/Classes/data/classKeywordOrderNoErrors.php
new file mode 100644
index 000000000..163ac1750
--- /dev/null
+++ b/tests/Sniffs/Classes/data/classKeywordOrderNoErrors.php
@@ -0,0 +1,56 @@
+<?php // lint >= 8.2
+
+class Foo1
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+final class Foo2
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+readonly class Foo3
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+final readonly class Foo4
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+
+abstract class Foo5
+{
+
+	public function bar()
+	{
+
+	}
+}
+
+abstract readonly class Foo6
+{
+
+	public function bar()
+	{
+
+	}
+}