diff --git a/src/Service/Syntax/Constraints/BooleanType/BooleanType.php b/src/Service/Syntax/Constraints/BooleanType/BooleanType.php
new file mode 100644
index 0000000..2a930aa
--- /dev/null
+++ b/src/Service/Syntax/Constraints/BooleanType/BooleanType.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Blugen\Service\Syntax\Constraints\BooleanType;
+
+use Attribute;
+use Blugen\Service\Syntax\Constraints\LexConstraint;
+use Symfony\Component\Validator\Constraint;
+
+#[Attribute(Attribute::TARGET_PROPERTY)]
+class BooleanType extends Constraint implements LexConstraint
+{
+    use \Blugen\Service\Syntax\Constraints\Constraint;
+
+    public string $message = 'Expected boolean value {{ must }}, but got {{ actual }}';
+}
diff --git a/src/Service/Syntax/Constraints/BooleanType/BooleanTypeValidator.php b/src/Service/Syntax/Constraints/BooleanType/BooleanTypeValidator.php
new file mode 100644
index 0000000..7be8835
--- /dev/null
+++ b/src/Service/Syntax/Constraints/BooleanType/BooleanTypeValidator.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Blugen\Service\Syntax\Constraints\BooleanType;
+
+use Blugen\Service\Lexicon\V1\Schema;
+use Blugen\Service\Lexicon\V1\TypeSpecificSchema\Field\BooleanSchema;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+class BooleanTypeValidator extends ConstraintValidator
+{
+    public function validate(mixed $value, Constraint $constraint)
+    {
+        if (! $constraint instanceof BooleanType) {
+            throw new UnexpectedTypeException($constraint, BooleanType::class);
+        }
+
+        if (! is_bool($value)) {
+            throw new UnexpectedTypeException($value, 'boolean');
+        }
+
+        $schema = new BooleanSchema(new Schema($constraint->schema()));
+
+        if (! is_null($const = $schema->const()) && $value !== $const) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ actual }}', $this->formatValue($value))
+                ->setParameter('{{ must }}', $this->formatValue($const))
+                ->addViolation();
+        }
+    }
+}
diff --git a/tests/Unit/Service/Syntax/Constraints/BooleanTypeTest.php b/tests/Unit/Service/Syntax/Constraints/BooleanTypeTest.php
new file mode 100644
index 0000000..15695f4
--- /dev/null
+++ b/tests/Unit/Service/Syntax/Constraints/BooleanTypeTest.php
@@ -0,0 +1,102 @@
+<?php
+
+namespace Blugen\Tests\Unit\Service\Syntax\Constraints;
+
+use Blugen\Service\Syntax\Constraints\BooleanType\BooleanType;
+use Blugen\Service\Syntax\Constraints\BooleanType\BooleanTypeValidator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use stdClass;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+class BooleanTypeTest extends ConstraintValidatorTestCase
+{
+    protected function createValidator(): BooleanTypeValidator
+    {
+        return new BooleanTypeValidator();
+    }
+
+    #[DataProvider('validBooleanProvider')]
+    public function test_valid_boolean_values(bool $value): void
+    {
+        $constraint = new BooleanType();
+
+        $this->validator->validate($value, $constraint);
+
+        $this->assertNoViolation();
+    }
+
+    public static function validBooleanProvider(): array
+    {
+        return [
+            [true],
+            [false],
+        ];
+    }
+
+    #[DataProvider('invalidBooleanProvider')]
+    public function test_invalid_boolean_values(mixed $invalidValue): void
+    {
+        $this->expectException(UnexpectedTypeException::class);
+
+        $constraint = new BooleanType();
+        $this->validator->validate($invalidValue, $constraint);
+    }
+
+    public static function invalidBooleanProvider(): array
+    {
+        return [
+            ['string'],
+            [1.4],
+            [1],
+            [new stdClass()],
+            [[]],
+            [null],
+        ];
+    }
+
+    public function test_violation_when_const_not_matching_value(): void
+    {
+        $constraint = new BooleanType([
+            'type' => 'boolean',
+            'const' => false,
+        ]);
+
+        $this->validator->validate(true, $constraint);
+
+        $this->buildViolation($constraint->message)
+            ->setParameter('{{ actual }}', 'true')
+            ->setParameter('{{ must }}', 'false')
+            ->assertRaised();
+    }
+
+    public function test_valid_when_value_matches_const(): void
+    {
+        $constraint = new BooleanType([
+            'type' => 'boolean',
+            'const' => false,
+        ]);
+
+        $this->validator->validate(false, $constraint);
+
+        $this->assertNoViolation();
+    }
+
+    public function test_false_value_is_valid(): void
+    {
+        $constraint = new BooleanType();
+
+        $this->validator->validate(false, $constraint);
+
+        $this->assertNoViolation();
+    }
+
+    public function test_true_value_is_valid(): void
+    {
+        $constraint = new BooleanType();
+
+        $this->validator->validate(true, $constraint);
+
+        $this->assertNoViolation();
+    }
+}