diff --git a/src/Validator/Constraints/BelgianEnterpriseNumber.php b/src/Validator/Constraints/BelgianEnterpriseNumber.php
new file mode 100644
index 0000000..3902969
--- /dev/null
+++ b/src/Validator/Constraints/BelgianEnterpriseNumber.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AssoConnect\ValidatorBundle\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+
+#[\Attribute(\Attribute::TARGET_PROPERTY | \Attribute::TARGET_METHOD)]
+class BelgianEnterpriseNumber extends Constraint
+{
+    public const string WRONG_FORMAT_ERROR = '3f7d2e1c-a845-4b9f-c631-52d78e04fb6a';
+    public const string MESSAGE = 'The Belgian Enterprise Number {{ value }} is not valid.';
+}
diff --git a/src/Validator/Constraints/BelgianEnterpriseNumberValidator.php b/src/Validator/Constraints/BelgianEnterpriseNumberValidator.php
new file mode 100644
index 0000000..cb52ab4
--- /dev/null
+++ b/src/Validator/Constraints/BelgianEnterpriseNumberValidator.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AssoConnect\ValidatorBundle\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
+
+class BelgianEnterpriseNumberValidator extends ConstraintValidator
+{
+    public function validate(mixed $value, Constraint $constraint): void
+    {
+        if (!$constraint instanceof BelgianEnterpriseNumber) {
+            throw new UnexpectedTypeException($constraint, BelgianEnterpriseNumber::class);
+        }
+
+        if (null === $value || '' === $value) {
+            return;
+        }
+
+        if (!is_string($value)) {
+            throw new UnexpectedValueException($value, 'string');
+        }
+
+        if (!ctype_digit($value) || strlen($value) !== 10 || !in_array($value[0], ['0', '1'], true)) {
+            $this->context->buildViolation($constraint::MESSAGE)
+                ->setParameter('{{ value }}', $this->formatValue($value))
+                ->setCode($constraint::WRONG_FORMAT_ERROR)
+                ->addViolation();
+        }
+    }
+}
diff --git a/tests/Validator/Constraints/BelgianEnterpriseNumberValidatorTest.php b/tests/Validator/Constraints/BelgianEnterpriseNumberValidatorTest.php
new file mode 100644
index 0000000..6192587
--- /dev/null
+++ b/tests/Validator/Constraints/BelgianEnterpriseNumberValidatorTest.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AssoConnect\ValidatorBundle\Tests\Validator\Constraints;
+
+use AssoConnect\ValidatorBundle\Test\ConstraintValidatorTestCase;
+use AssoConnect\ValidatorBundle\Validator\Constraints\BelgianEnterpriseNumber;
+use AssoConnect\ValidatorBundle\Validator\Constraints\BelgianEnterpriseNumberValidator;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+
+/**
+ * @extends ConstraintValidatorTestCase<BelgianEnterpriseNumberValidator>
+ */
+class BelgianEnterpriseNumberValidatorTest extends ConstraintValidatorTestCase
+{
+    protected function getConstraint(): Constraint
+    {
+        return new BelgianEnterpriseNumber();
+    }
+
+    public function createValidator(): ConstraintValidator
+    {
+        return new BelgianEnterpriseNumberValidator();
+    }
+
+    public static function providerValidValues(): iterable
+    {
+        yield 'null value' => [null];
+        yield 'empty string' => [''];
+        yield 'valid number starting with 0' => ['0123456789'];
+        yield 'valid number starting with 1' => ['1234567890'];
+        yield 'valid number starting with 0 all zeros' => ['0000000000'];
+        yield 'valid number starting with 1 all digits' => ['1999999999'];
+    }
+
+    public static function providerInvalidValues(): iterable
+    {
+        $expectedMessage = BelgianEnterpriseNumber::MESSAGE;
+        $code = BelgianEnterpriseNumber::WRONG_FORMAT_ERROR;
+
+        yield 'too short' => ['012345678', $code, $expectedMessage];
+        yield 'too long' => ['01234567890', $code, $expectedMessage];
+        yield 'starts with 2' => ['2123456789', $code, $expectedMessage];
+        yield 'starts with 9' => ['9123456789', $code, $expectedMessage];
+        yield 'contains letters' => ['012345678A', $code, $expectedMessage];
+        yield 'contains special characters' => ['01234-6789', $code, $expectedMessage];
+        yield 'contains spaces' => ['0123 56789', $code, $expectedMessage];
+        yield 'single digit' => ['0', $code, $expectedMessage];
+    }
+}