diff --git a/src/Validation/RequestValidator/RequestParameterValidator.php b/src/Validation/RequestValidator/RequestParameterValidator.php
index 7615ca6..2501772 100644
--- a/src/Validation/RequestValidator/RequestParameterValidator.php
+++ b/src/Validation/RequestValidator/RequestParameterValidator.php
@@ -78,7 +78,7 @@ private function getValidateQueryParametersFromRequest(Request $request): array
     private function validateQueryParameter(Request $request, string $parameterName, stdClass $parameter): array
     {
         $violations = [];
-        if ($request->query->has($parameterName) === false && $parameter->required ?? false) {
+        if (($parameter->required ?? false) && $request->query->has($parameterName) === false) {
             $violations[] = new Violation(
                 'required_query_parameter',
                 sprintf('Query parameter %s is required.', $parameterName),
@@ -93,6 +93,9 @@ private function validateQueryParameter(Request $request, string $parameterName,
         }
 
         $parameterValue = $request->query->get($parameterName);
+        if ($parameter->schema->type === 'boolean') {
+            $parameterValue = $request->query->getBoolean($parameterName, $parameter->schema->default ?? false);
+        }
 
         $this->jsonValidator->validate($parameterValue, $parameter->schema, Constraint::CHECK_MODE_COERCE_TYPES);
         if ($this->jsonValidator->isValid()) {
diff --git a/tests/Validation/RequestValidator/RequestParameterValidatorTest.php b/tests/Validation/RequestValidator/RequestParameterValidatorTest.php
index 1997bcf..e1ed870 100644
--- a/tests/Validation/RequestValidator/RequestParameterValidatorTest.php
+++ b/tests/Validation/RequestValidator/RequestParameterValidatorTest.php
@@ -91,6 +91,29 @@ public function testCannotValidateRequiredRequestParameterWithoutValue(): void
         );
     }
 
+    public function testCanValidateOptionalRequestParameterWithoutRequiredFlag(): void
+    {
+        $request = new Request();
+        $request->attributes->set(
+            RouteContext::REQUEST_ATTRIBUTE,
+            [
+                RouteContext::REQUEST_VALIDATE_QUERY_PARAMETERS => [
+                    'foo' => json_encode([
+                        'name' => 'foo',
+                        'in' => 'query',
+                        'schema' => [
+                            'type' => 'string',
+                        ],
+                    ]),
+                ],
+            ]
+        );
+
+        static::assertNull(
+            $this->validator->validate($request)
+        );
+    }
+
     public function testCanValidateRequestParameterOfTypeBoolean(): void
     {
         $request = new Request();
@@ -116,6 +139,31 @@ public function testCanValidateRequestParameterOfTypeBoolean(): void
         );
     }
 
+    public function testCanValidateRequestParameterOfTypeBooleanWithOne(): void
+    {
+        $request = new Request();
+        $request->query->set('foo', '1');
+        $request->attributes->set(
+            RouteContext::REQUEST_ATTRIBUTE,
+            [
+                RouteContext::REQUEST_VALIDATE_QUERY_PARAMETERS => [
+                    'foo' => json_encode([
+                        'name' => 'foo',
+                        'in' => 'query',
+                        'required' => true,
+                        'schema' => [
+                            'type' => 'boolean',
+                        ],
+                    ]),
+                ],
+            ]
+        );
+
+        static::assertNull(
+            $this->validator->validate($request)
+        );
+    }
+
     public function testCanValidateRequestParameterOfTypeString(): void
     {
         $request = new Request();