diff --git a/lib/jmap/mail/calendar/reply/calendar_event_reject_method.dart b/lib/jmap/mail/calendar/reply/calendar_event_reject_method.dart
new file mode 100644
index 0000000..025776a
--- /dev/null
+++ b/lib/jmap/mail/calendar/reply/calendar_event_reject_method.dart
@@ -0,0 +1,28 @@
+import 'package:jmap_dart_client/http/converter/account_id_converter.dart';
+import 'package:jmap_dart_client/http/converter/id_converter.dart';
+import 'package:jmap_dart_client/jmap/core/capability/capability_identifier.dart';
+import 'package:jmap_dart_client/jmap/core/method/request/calendar_event_reply_method.dart';
+import 'package:jmap_dart_client/jmap/core/request/request_invocation.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'calendar_event_reject_method.g.dart';
+
+@JsonSerializable(converters: [
+  AccountIdConverter(),
+  IdConverter(),
+])
+class CalendarEventRejectMethod extends CalendarEventReplyMethod {
+  CalendarEventRejectMethod(super.accountId, {required super.blobIds});
+
+  @override
+  MethodName get methodName => MethodName('CalendarEvent/reject');
+
+  @override
+  Set<CapabilityIdentifier> get requiredCapabilities => {
+    CapabilityIdentifier.jmapCore,
+    CapabilityIdentifier.jamesCalendarEvent
+  };
+
+  @override
+  Map<String, dynamic> toJson() => _$CalendarEventRejectMethodToJson(this);
+}
\ No newline at end of file
diff --git a/lib/jmap/mail/calendar/reply/calendar_event_reject_method.g.dart b/lib/jmap/mail/calendar/reply/calendar_event_reject_method.g.dart
new file mode 100644
index 0000000..963ec63
--- /dev/null
+++ b/lib/jmap/mail/calendar/reply/calendar_event_reject_method.g.dart
@@ -0,0 +1,33 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'calendar_event_reject_method.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+CalendarEventRejectMethod _$CalendarEventRejectMethodFromJson(
+        Map<String, dynamic> json) =>
+    CalendarEventRejectMethod(
+      const AccountIdConverter().fromJson(json['accountId'] as String),
+      blobIds: (json['blobIds'] as List<dynamic>)
+          .map((e) => const IdConverter().fromJson(e as String))
+          .toList(),
+    )..language = json['language'] as String?;
+
+Map<String, dynamic> _$CalendarEventRejectMethodToJson(
+    CalendarEventRejectMethod instance) {
+  final val = <String, dynamic>{
+    'accountId': const AccountIdConverter().toJson(instance.accountId),
+  };
+
+  void writeNotNull(String key, dynamic value) {
+    if (value != null) {
+      val[key] = value;
+    }
+  }
+
+  writeNotNull('language', instance.language);
+  val['blobIds'] = instance.blobIds.map(const IdConverter().toJson).toList();
+  return val;
+}
diff --git a/lib/jmap/mail/calendar/reply/calendar_event_reject_response.dart b/lib/jmap/mail/calendar/reply/calendar_event_reject_response.dart
new file mode 100644
index 0000000..3314a9b
--- /dev/null
+++ b/lib/jmap/mail/calendar/reply/calendar_event_reject_response.dart
@@ -0,0 +1,29 @@
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:jmap_dart_client/jmap/core/method/response/calendar_event_reply_response.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/properties/event_id.dart';
+import 'package:jmap_dart_client/util/json_parsers.dart';
+
+class CalendarEventRejectResponse extends CalendarEventReplyResponse {
+  CalendarEventRejectResponse(
+    super.accountId,
+    super.notFound,
+    {
+      this.rejected,
+      this.notRejected
+    });
+
+  final List<EventId>? rejected;
+  final List<Id>? notRejected;
+
+  static CalendarEventRejectResponse deserialize(Map<String, dynamic> json) {
+    return CalendarEventRejectResponse(
+      JsonParsers().parsingAccountId(json),
+      JsonParsers().parsingListId(json, 'notFound'),
+      rejected: JsonParsers().parsingListEventId(json, 'rejected'),
+      notRejected: JsonParsers().parsingListId(json, 'notRejected'),
+    );
+  }
+
+  @override
+  List<Object?> get props => [...super.props, rejected, notRejected];
+}
\ No newline at end of file
diff --git a/test/jmap/mail/calendar/reply/calendar_event_reject_method_test.dart b/test/jmap/mail/calendar/reply/calendar_event_reject_method_test.dart
new file mode 100644
index 0000000..5587a0d
--- /dev/null
+++ b/test/jmap/mail/calendar/reply/calendar_event_reject_method_test.dart
@@ -0,0 +1,91 @@
+import 'package:dio/dio.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http_mock_adapter/http_mock_adapter.dart';
+import 'package:jmap_dart_client/http/http_client.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:jmap_dart_client/jmap/core/method/request/calendar_event_reply_method.dart';
+import 'package:jmap_dart_client/jmap/core/method/response/calendar_event_reply_response.dart';
+import 'package:jmap_dart_client/jmap/core/request/request_invocation.dart';
+import 'package:jmap_dart_client/jmap/jmap_request.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/properties/event_id.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_reject_method.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_reject_response.dart';
+
+void main() {
+  final baseOption = BaseOptions(method: 'POST');
+  final dio = Dio(baseOption)..options.baseUrl = 'http://domain.com/jmap';
+  final dioAdapter = DioAdapter(dio: dio);
+  final dioAdapterHeaders = {"accept": "application/json;jmapVersion=rfc-8621"};
+  final httpClient = HttpClient(dio);
+  final processingInvocation = ProcessingInvocation();
+  final requestBuilder = JmapRequestBuilder(httpClient, processingInvocation);
+  final accountId = AccountId(Id('123abc'));
+  final successBlobId = Id('abc123');
+  final failureBlobId = Id('def456');
+  final notFoundBlobId = Id('ghi789');
+  final blobIds = [successBlobId, failureBlobId, notFoundBlobId];
+  final methodCallId = MethodCallId('c0');
+
+  Map<String, dynamic> constructData(CalendarEventReplyMethod method) => {
+    "using": method.requiredCapabilities
+      .map((capability) => capability.value.toString())
+      .toList(),
+    "methodCalls": [
+      [
+        method.methodName.value,
+        {
+          "accountId": accountId.id.value,
+          "blobIds": blobIds.map((id) => id.value).toList(),
+        },
+        methodCallId.value
+      ]
+    ]
+  };
+
+  Map<String, dynamic> constructResponse(CalendarEventReplyMethod method) => {
+    "sessionState": "abcdefghij",
+    "methodResponses": [[
+      method.methodName.value,
+      {
+        "accountId": accountId.id.value,
+        "rejected": [successBlobId.value],
+        "notRejected": [failureBlobId.value],
+        "notFound": [notFoundBlobId.value],
+      },
+      methodCallId.value
+    ]]
+  };
+
+  group('calendar event reject method', () {
+    final method = CalendarEventRejectMethod(accountId, blobIds: blobIds);
+
+    test('should succeed with success blob data, '
+    'and fail with failure blob data '
+    'and not found with not found blob data', () async {
+      // arrange
+      final invocation = requestBuilder.invocation(method, methodCallId: methodCallId);
+      dioAdapter.onPost(
+        '',
+        (server) => server.reply(200, constructResponse(method)),
+        data: constructData(method),
+        headers: dioAdapterHeaders,
+      );
+
+      // act
+      final response = (await (requestBuilder..usings(method.requiredCapabilities))
+        .build()
+        .execute())
+          .parse<CalendarEventReplyResponse>(
+            invocation.methodCallId,
+            CalendarEventRejectResponse.deserialize); 
+      
+      // assert
+      expect(
+        (response as CalendarEventRejectResponse?)?.rejected,
+        equals([EventId(successBlobId.value)]));
+      expect(response?.notRejected, equals([failureBlobId]));
+      expect(response?.notFound, equals([notFoundBlobId]));
+    });
+  });
+}
\ No newline at end of file