diff --git a/chopper/example/definition.chopper.dart b/chopper/example/definition.chopper.dart
index 0a26d4a8..f43a754d 100644
--- a/chopper/example/definition.chopper.dart
+++ b/chopper/example/definition.chopper.dart
@@ -6,7 +6,7 @@ part of 'definition.dart';
 // ChopperGenerator
 // **************************************************************************
 
-// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations
+// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations, unnecessary_brace_in_string_interps
 class _$MyService extends MyService {
   _$MyService([ChopperClient? client]) {
     if (client == null) return;
@@ -18,7 +18,7 @@ class _$MyService extends MyService {
 
   @override
   Future<Response<dynamic>> getResource(String id) {
-    final $url = '/resources/$id';
+    final $url = '/resources/${id}';
     final $request = Request('GET', $url, client.baseUrl);
     return client.send<dynamic, dynamic>($request);
   }
diff --git a/chopper/test/base_test.dart b/chopper/test/base_test.dart
index b591168a..24487c36 100644
--- a/chopper/test/base_test.dart
+++ b/chopper/test/base_test.dart
@@ -591,6 +591,165 @@ void main() {
     });
   });
 
+  test('Query Map 3', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?name=foo&number=1234'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest3(
+      name: 'foo',
+      number: 1234,
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 4 without QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?name=foo&number=1234'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest4(
+      name: 'foo',
+      number: 1234,
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 4 with QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals(
+          '$baseUrl/test/query_map?name=foo&number=1234&filter_1=filter_value_1',
+        ),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest4(
+      name: 'foo',
+      number: 1234,
+      filters: {
+        'filter_1': 'filter_value_1',
+      },
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test(
+    'Query Map 4 with QueryMap that overwrites a previous value from Query',
+    () async {
+      final httpClient = MockClient((request) async {
+        expect(
+          request.url.toString(),
+          equals('$baseUrl/test/query_map?name=bar&number=1234'),
+        );
+        expect(request.method, equals('GET'));
+
+        return http.Response('get response', 200);
+      });
+
+      final chopper = buildClient(httpClient);
+      final service = chopper.getService<HttpTestService>();
+
+      final response = await service.getQueryMapTest4(
+        name: 'foo',
+        number: 1234,
+        filters: {
+          'name': 'bar',
+        },
+      );
+
+      expect(response.body, equals('get response'));
+      expect(response.statusCode, equals(200));
+
+      httpClient.close();
+    },
+  );
+
+  test('Query Map 5 without QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest5();
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 5 with QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?filter_1=filter_value_1'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest5(
+      filters: {
+        'filter_1': 'filter_value_1',
+      },
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
   test('onRequest Stream', () async {
     final client = MockClient((http.Request req) async {
       return http.Response('ok', 200);
diff --git a/chopper/test/test_service.chopper.dart b/chopper/test/test_service.chopper.dart
index 2d03d152..f1fd6769 100644
--- a/chopper/test/test_service.chopper.dart
+++ b/chopper/test/test_service.chopper.dart
@@ -6,7 +6,7 @@ part of 'test_service.dart';
 // ChopperGenerator
 // **************************************************************************
 
-// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations
+// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations, unnecessary_brace_in_string_interps
 class _$HttpTestService extends HttpTestService {
   _$HttpTestService([ChopperClient? client]) {
     if (client == null) return;
@@ -18,7 +18,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<String>> getTest(String id, {required String dynamicHeader}) {
-    final $url = '/test/get/$id';
+    final $url = '/test/get/${id}';
     final $headers = {
       'test': dynamicHeader,
     };
@@ -93,6 +93,36 @@ class _$HttpTestService extends HttpTestService {
     return client.send<dynamic, dynamic>($request);
   }
 
+  @override
+  Future<Response<dynamic>> getQueryMapTest3(
+      {String name = '',
+      int? number,
+      Map<String, dynamic> filters = const {}}) {
+    final $url = '/test/query_map';
+    final $params = <String, dynamic>{'name': name, 'number': number};
+    $params.addAll(filters);
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
+  @override
+  Future<Response<dynamic>> getQueryMapTest4(
+      {String name = '', int? number, Map<String, dynamic>? filters}) {
+    final $url = '/test/query_map';
+    final $params = <String, dynamic>{'name': name, 'number': number};
+    $params.addAll(filters ?? {});
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
+  @override
+  Future<Response<dynamic>> getQueryMapTest5({Map<String, dynamic>? filters}) {
+    final $url = '/test/query_map';
+    final $params = filters ?? {};
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
   @override
   Future<Response<dynamic>> getBody(dynamic body) {
     final $url = '/test/get_body';
@@ -119,7 +149,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> putTest(String test, String data) {
-    final $url = '/test/put/$test';
+    final $url = '/test/put/${test}';
     final $body = data;
     final $request = Request('PUT', $url, client.baseUrl, body: $body);
     return client.send<dynamic, dynamic>($request);
@@ -127,7 +157,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> deleteTest(String id) {
-    final $url = '/test/delete/$id';
+    final $url = '/test/delete/${id}';
     final $headers = {
       'foo': 'bar',
     };
@@ -138,7 +168,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> patchTest(String id, String data) {
-    final $url = '/test/patch/$id';
+    final $url = '/test/patch/${id}';
     final $body = data;
     final $request = Request('PATCH', $url, client.baseUrl, body: $body);
     return client.send<dynamic, dynamic>($request);
diff --git a/chopper/test/test_service.dart b/chopper/test/test_service.dart
index 1c68866a..fa137441 100644
--- a/chopper/test/test_service.dart
+++ b/chopper/test/test_service.dart
@@ -48,6 +48,25 @@ abstract class HttpTestService extends ChopperService {
     @Query('test') bool? test,
   });
 
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest3({
+    @Query('name') String name = '',
+    @Query('number') int? number,
+    @QueryMap() Map<String, dynamic> filters = const {},
+  });
+
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest4({
+    @Query('name') String name = '',
+    @Query('number') int? number,
+    @QueryMap() Map<String, dynamic>? filters,
+  });
+
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest5({
+    @QueryMap() Map<String, dynamic>? filters,
+  });
+
   @Get(path: 'get_body')
   Future<Response> getBody(@Body() dynamic body);
 
diff --git a/chopper_generator/lib/src/generator.dart b/chopper_generator/lib/src/generator.dart
index a3ae9880..ab95ee80 100644
--- a/chopper_generator/lib/src/generator.dart
+++ b/chopper_generator/lib/src/generator.dart
@@ -10,6 +10,7 @@ import 'package:built_collection/built_collection.dart';
 import 'package:dart_style/dart_style.dart';
 
 import 'package:source_gen/source_gen.dart';
+
 // TODO(lejard_h) Code builder not null safe yet
 // ignore: import_of_legacy_library_into_null_safe
 import 'package:code_builder/code_builder.dart';
@@ -171,15 +172,34 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         blocks.add(_generateMap(queries).assignFinal(_parametersVar).statement);
       }
 
+      // Build an iterable of all the parameters that are nullable
+      final optionalNullableParameters = [
+        ...m.parameters.where((p) => p.isOptionalPositional),
+        ...m.parameters.where((p) => p.isNamed),
+      ].where((el) => el.type.isNullable).map((el) => el.name);
+
       final hasQueryMap = queryMap.isNotEmpty;
       if (hasQueryMap) {
         if (queries.isNotEmpty) {
           blocks.add(refer('$_parametersVar.addAll').call(
-            [refer(queryMap.keys.first)],
+            [
+              // Check if the parameter is nullable
+              optionalNullableParameters.contains(queryMap.keys.first)
+                  ? refer(queryMap.keys.first).ifNullThen(refer('{}'))
+                  : refer(queryMap.keys.first),
+            ],
           ).statement);
         } else {
           blocks.add(
-            refer(queryMap.keys.first).assignFinal(_parametersVar).statement,
+            // Check if the parameter is nullable
+            optionalNullableParameters.contains(queryMap.keys.first)
+                ? refer(queryMap.keys.first)
+                    .ifNullThen(refer('{}'))
+                    .assignFinal(_parametersVar)
+                    .statement
+                : refer(queryMap.keys.first)
+                    .assignFinal(_parametersVar)
+                    .statement,
           );
         }
       }