diff --git a/lib/features/email/data/datasource_impl/calendar_event_datasource_impl.dart b/lib/features/email/data/datasource_impl/calendar_event_datasource_impl.dart
index 4962263db6..fac76189d0 100644
--- a/lib/features/email/data/datasource_impl/calendar_event_datasource_impl.dart
+++ b/lib/features/email/data/datasource_impl/calendar_event_datasource_impl.dart
@@ -3,6 +3,7 @@ import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:jmap_dart_client/jmap/core/id.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/calendar_event.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_accept_response.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_reject_response.dart';
 import 'package:tmail_ui_user/features/email/data/datasource/calendar_event_datasource.dart';
 import 'package:tmail_ui_user/features/email/data/network/calendar_event_api.dart';
 import 'package:tmail_ui_user/features/email/domain/model/event_action.dart';
@@ -33,4 +34,11 @@ class CalendarEventDataSourceImpl extends CalendarEventDataSource {
       return await _calendarEventAPI.accept(accountId, blobIds);
     }).catchError(_exceptionThrower.throwException);
   }
+
+  @override
+  Future<CalendarEventRejectResponse> rejectEventInvitation(AccountId accountId, Set<Id> blobIds) {
+    return Future.sync(() async {
+      return await _calendarEventAPI.reject(accountId, blobIds);
+    }).catchError(_exceptionThrower.throwException);
+  }
 }
\ No newline at end of file
diff --git a/lib/features/email/data/datasource_impl/local_calendar_event_datasource_impl.dart b/lib/features/email/data/datasource_impl/local_calendar_event_datasource_impl.dart
index dcfaf7a99e..d1300ec549 100644
--- a/lib/features/email/data/datasource_impl/local_calendar_event_datasource_impl.dart
+++ b/lib/features/email/data/datasource_impl/local_calendar_event_datasource_impl.dart
@@ -3,6 +3,7 @@ import 'package:jmap_dart_client/jmap/account_id.dart';
 import 'package:jmap_dart_client/jmap/core/id.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/calendar_event.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_accept_response.dart';
+import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_reject_response.dart';
 import 'package:tmail_ui_user/features/email/data/datasource/calendar_event_datasource.dart';
 import 'package:tmail_ui_user/features/email/data/local/html_analyzer.dart';
 import 'package:tmail_ui_user/features/email/domain/model/event_action.dart';
@@ -31,4 +32,9 @@ class LocalCalendarEventDataSourceImpl extends CalendarEventDataSource {
   Future<CalendarEventAcceptResponse> accept(AccountId accountId, Set<Id> blobIds) {
     throw UnimplementedError();
   }
+  
+  @override
+  Future<CalendarEventRejectResponse> rejectEventInvitation(AccountId accountId, Set<Id> blobIds) {
+    throw UnimplementedError();
+  }
 }
\ No newline at end of file
diff --git a/lib/features/email/data/network/calendar_event_api.dart b/lib/features/email/data/network/calendar_event_api.dart
index 46595544fc..8104fc7142 100644
--- a/lib/features/email/data/network/calendar_event_api.dart
+++ b/lib/features/email/data/network/calendar_event_api.dart
@@ -9,6 +9,8 @@ import 'package:jmap_dart_client/jmap/mail/calendar/parse/calendar_event_parse_m
 import 'package:jmap_dart_client/jmap/mail/calendar/parse/calendar_event_parse_response.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_accept_method.dart';
 import 'package:jmap_dart_client/jmap/mail/calendar/reply/calendar_event_accept_response.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';
 import 'package:tmail_ui_user/features/email/domain/exceptions/calendar_event_exceptions.dart';
 
 class CalendarEventAPI {
@@ -61,4 +63,25 @@ class CalendarEventAPI {
 
     return calendarEventAcceptResponse;
   }
+
+  Future<CalendarEventRejectResponse> reject(AccountId accountId, Set<Id> blobIds) async {
+    final requestBuilder = JmapRequestBuilder(_httpClient, ProcessingInvocation());
+    final calendarEventRejectMethod = CalendarEventRejectMethod(
+      accountId,
+      blobIds: blobIds.toList());
+    final calendarEventRejectInvocation = requestBuilder.invocation(calendarEventRejectMethod);
+    final response = await (requestBuilder..usings(calendarEventRejectMethod.requiredCapabilities))
+      .build()
+      .execute();
+
+    final calendarEventRejectResponse = response.parse<CalendarEventRejectResponse>(
+      calendarEventRejectInvocation.methodCallId,
+      CalendarEventRejectResponse.deserialize);
+
+    if (calendarEventRejectResponse == null) {
+      throw NotRejectableCalendarEventException();
+    }
+
+    return calendarEventRejectResponse;
+  }
 }
\ No newline at end of file
diff --git a/lib/features/email/domain/exceptions/calendar_event_exceptions.dart b/lib/features/email/domain/exceptions/calendar_event_exceptions.dart
index 02078195aa..a472a5084f 100644
--- a/lib/features/email/domain/exceptions/calendar_event_exceptions.dart
+++ b/lib/features/email/domain/exceptions/calendar_event_exceptions.dart
@@ -4,3 +4,5 @@ class NotFoundCalendarEventException implements Exception {}
 class NotParsableCalendarEventException implements Exception {}
 
 class NotAcceptableCalendarEventException implements Exception {}
+
+class NotRejectableCalendarEventException implements Exception {}