diff --git a/OpenApiPhp/Util.php b/OpenApiPhp/Util.php
index 6cf7a48..ba97ede 100644
--- a/OpenApiPhp/Util.php
+++ b/OpenApiPhp/Util.php
@@ -346,10 +346,17 @@ final class Util
     {
         $done = [];
 
+        $defaults = \get_class_vars(\get_class($annotation));
+
         foreach ($annotation::$_nested as $className => $propertyName) {
             if (\is_string($propertyName)) {
                 if (array_key_exists($propertyName, $properties)) {
-                    self::mergeChild($annotation, $className, $properties[$propertyName], $overwrite);
+                    if (!is_bool($properties[$propertyName])) {
+                        self::mergeChild($annotation, $className, $properties[$propertyName], $overwrite);
+                    } elseif ($overwrite || $annotation->{$propertyName} === $defaults[$propertyName]) {
+                        // Support for boolean values (for instance for additionalProperties)
+                        $annotation->{$propertyName} = $properties[$propertyName];
+                    }
                     $done[] = $propertyName;
                 }
             } elseif (\array_key_exists($propertyName[0], $properties)) {
@@ -360,8 +367,6 @@ final class Util
             }
         }
 
-        $defaults = \get_class_vars(\get_class($annotation));
-
         foreach ($annotation::$_types as $propertyName => $type) {
             if (array_key_exists($propertyName, $properties)) {
                 self::mergeTyped($annotation, $propertyName, $type, $properties, $defaults, $overwrite);
diff --git a/Tests/Functional/FunctionalTest.php b/Tests/Functional/FunctionalTest.php
index 9570edf..8b2b372 100644
--- a/Tests/Functional/FunctionalTest.php
+++ b/Tests/Functional/FunctionalTest.php
@@ -543,4 +543,11 @@ class FunctionalTest extends WebTestCase
         $this->getModel('SymfonyDiscriminatorOne');
         $this->getModel('SymfonyDiscriminatorTwo');
     }
+
+    public function testNoAdditionalPropertiesSupport()
+    {
+        $model = $this->getModel('AddProp');
+
+        $this->assertFalse($model->additionalProperties);
+    }
 }
diff --git a/Tests/Functional/TestKernel.php b/Tests/Functional/TestKernel.php
index f89f6f0..9e3a79f 100644
--- a/Tests/Functional/TestKernel.php
+++ b/Tests/Functional/TestKernel.php
@@ -198,6 +198,10 @@ class TestKernel extends Kernel
                                 ['type' => 'object'],
                             ],
                         ],
+                        'AddProp' => [
+                            'type' => 'object',
+                            'additionalProperties' => false,
+                        ],
                     ],
                     'parameters' => [
                         'test' => [