diff --git a/src/Writing/OpenAPISpecWriter.php b/src/Writing/OpenAPISpecWriter.php
index 509c01f0..0a347133 100644
--- a/src/Writing/OpenAPISpecWriter.php
+++ b/src/Writing/OpenAPISpecWriter.php
@@ -456,9 +456,11 @@ public function generateFieldData($field): array
             $field = new Parameter($field);
         }
 
+        $fieldData = [];
+
         if ($field->type === 'file') {
             // See https://swagger.io/docs/specification/describing-request-body/file-upload/
-            return [
+            $fieldData = [
                 'type' => 'string',
                 'format' => 'binary',
                 'description' => $field->description ?: '',
@@ -498,10 +500,8 @@ public function generateFieldData($field): array
                     }
                 }
             }
-
-            return $fieldData;
         } else if ($field->type === 'object') {
-            return [
+            $fieldData = [
                 'type' => 'object',
                 'description' => $field->description ?: '',
                 'example' => $field->example,
@@ -510,17 +510,20 @@ public function generateFieldData($field): array
                 })->all()),
             ];
         } else {
-            $schema = [
+            $fieldData = [
                 'type' => static::normalizeTypeName($field->type),
                 'description' => $field->description ?: '',
                 'example' => $field->example,
             ];
             if (!empty($field->enumValues)) {
-                $schema['enum'] = $field->enumValues;
+                $fieldData['enum'] = $field->enumValues;
             }
+        }
 
-            return $schema;
+        if (isset($field['required']) && !$field['required']) {
+            $fieldData['nullable'] = true;
         }
+        return $fieldData;
     }
 
     protected function operationId(OutputEndpointData $endpoint): string
diff --git a/tests/Fixtures/openapi.yaml b/tests/Fixtures/openapi.yaml
index 9ea3a135..4ffc86bd 100644
--- a/tests/Fixtures/openapi.yaml
+++ b/tests/Fixtures/openapi.yaml
@@ -120,6 +120,7 @@ paths:
                     name: filters
                     description: 'The filters.'
                     example: consequatur
+                    nullable: true
                     required: false
                     schema:
                         type: string
@@ -130,6 +131,7 @@ paths:
                     name: url_encoded
                     description: 'Used for testing that URL parameters will be URL-encoded where needed.'
                     example: '+ []&='
+                    nullable: true
                     required: false
                     schema:
                         type: string
@@ -192,6 +194,7 @@ paths:
                         type: string
                         description: ''
                         example: consequatur
+                        nullable: true
                 -
                     in: header
                     name: Custom-Header
@@ -283,6 +286,7 @@ paths:
                         schema:
                             type: array
                             description: Details.
+                            nullable: true
                             example:
                             - first_name: 'John'
                               last_name: 'Doe'
diff --git a/tests/Unit/OpenAPISpecWriterTest.php b/tests/Unit/OpenAPISpecWriterTest.php
index 41990675..d5a20b17 100644
--- a/tests/Unit/OpenAPISpecWriterTest.php
+++ b/tests/Unit/OpenAPISpecWriterTest.php
@@ -234,6 +234,7 @@ public function adds_query_parameters_correctly_as_parameters_on_operation_objec
                 'type' => 'string',
                 'description' => 'A query param',
                 'example' => 'hahoho',
+                'nullable' => true,
             ],
         ], $results['paths']['/path1']['get']['parameters'][0]);
     }
@@ -341,6 +342,7 @@ public function adds_body_parameters_correctly_as_requestBody_on_operation_objec
                                 'description' => 'String param',
                                 'example' => 'hahoho',
                                 'type' => 'string',
+                                'nullable' => true,
                             ],
                             'booleanParam' => [
                                 'description' => 'Boolean param',
@@ -361,8 +363,10 @@ public function adds_body_parameters_correctly_as_requestBody_on_operation_objec
                                         'description' => 'Object param field',
                                         'example' => 119.0,
                                         'type' => 'number',
+                                        'nullable' => true,
                                     ],
                                 ],
+                                'nullable' => true,
                             ],
                         ],
                         'required' => [
@@ -384,11 +388,13 @@ public function adds_body_parameters_correctly_as_requestBody_on_operation_objec
                                 'description' => 'File param',
                                 'type' => 'string',
                                 'format' => 'binary',
+                                'nullable' => true,
                             ],
                             'numberArrayParam' => [
                                 'description' => 'Number array param',
                                 'example' => [186.9],
                                 'type' => 'array',
+                                'nullable' => true,
                                 'items' => [
                                     'type' => 'number',
                                 ],