diff --git a/src/ZipCodeValidator/Constraints/ZipCodeValidator.php b/src/ZipCodeValidator/Constraints/ZipCodeValidator.php
index a1a141c..8f4cc01 100644
--- a/src/ZipCodeValidator/Constraints/ZipCodeValidator.php
+++ b/src/ZipCodeValidator/Constraints/ZipCodeValidator.php
@@ -126,7 +126,7 @@ class ZipCodeValidator extends ConstraintValidator
         'LR' => '\\d{4}',
         'LS' => '\\d{3}',
         'LT' => '(LT-)?\\d{5}',
-        'LU' => '\\d{4}',
+        'LU' => '(L-)?\\d{4}',
         'LV' => '(LV-)?\\d{4}',
         'MA' => '\\d{5}',
         'MC' => '980\\d{2}',
diff --git a/tests/Constraints/LuZipCodeValidatorTest.php b/tests/Constraints/LuZipCodeValidatorTest.php
new file mode 100644
index 0000000..78ecc2e
--- /dev/null
+++ b/tests/Constraints/LuZipCodeValidatorTest.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ZipCodeValidator\Tests\Constraints;
+
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Validator\Context\ExecutionContext;
+use Symfony\Component\Validator\Violation\ConstraintViolationBuilderInterface;
+use ZipCodeValidator\Constraints\ZipCode;
+use ZipCodeValidator\Constraints\ZipCodeValidator;
+
+class LuZipCodeValidatorTest extends TestCase
+{
+    protected ZipCodeValidator $validator;
+
+    public function setUp(): void
+    {
+        $this->validator = new ZipCodeValidator;
+    }
+
+    /**
+     * @dataProvider getValidLuxembourgZipCodes
+     */
+    public function testValidZipcodes(string $zipCode): void
+    {
+        $constraint = new ZipCode('LU');
+
+        /** @var ExecutionContext|MockObject $contextMock */
+        $contextMock = $this->getMockBuilder(ExecutionContext::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        # be sure that buildViolation never gets called
+        $contextMock->expects($this->never())->method('buildViolation');
+        $contextMock->setConstraint($constraint);
+
+        $this->validator->initialize($contextMock);
+        $this->validator->validate($zipCode, $constraint);
+    }
+
+    /**
+     * Valid Luxembourg postal codes are four-digit numbers, optionally prefixed with "L-".
+     * @see https://www.post.lu/fr/particuliers/colis-courrier/bien-rediger-une-adresse
+     */
+    public static function getValidLuxembourgZipCodes(): array
+    {
+        return [
+            ['8211'],
+            ['L-8211'],
+            ['1234'],
+            ['L-1234'],
+        ];
+    }
+
+    /**
+     * @dataProvider getInvalidLuxembourgZipCodes
+     */
+    public function testInvalidZipcodes(string $zipCode): void
+    {
+        $constraint = new ZipCode('LU');
+
+        $violation = $this->createMock(ConstraintViolationBuilderInterface::class);
+        $violation->expects($this->once())->method('setParameter')->willReturnSelf();
+
+        /** @var ExecutionContext|MockObject $contextMock */
+        $contextMock = $this->getMockBuilder(ExecutionContext::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $contextMock->expects($this->once())->method('buildViolation')->willReturn($violation);
+        $contextMock->setConstraint($constraint);
+
+        $this->validator->initialize($contextMock);
+        $this->validator->validate($zipCode, $constraint);
+    }
+
+    /**
+     * Valid Luxembourg postal codes are four-digit numbers, optionally prefixed with "L-".
+     * @see https://www.post.lu/fr/particuliers/colis-courrier/bien-rediger-une-adresse
+     */
+    public static function getInvalidLuxembourgZipCodes(): array
+    {
+        return [
+            ['123'],
+            ['12345'],
+            ['L1234'],
+        ];
+    }
+}