diff --git a/lib/helpers/groups_helper.dart b/lib/helpers/groups_helper.dart
index 58ece46..26b9706 100644
--- a/lib/helpers/groups_helper.dart
+++ b/lib/helpers/groups_helper.dart
@@ -73,7 +73,7 @@ class GroupsHelper {
     // Check which groups information to download
     final toDownload = Set<int>();
     groups.forEach((groupID) {
-      if (_groupsListCache.containsKey(groupID))
+      if (!force && _groupsListCache.containsKey(groupID))
         list[groupID] = _groupsListCache[groupID];
       else
         toDownload.add(groupID);
@@ -101,8 +101,11 @@ class GroupsHelper {
           .toSet();
 
   /// Perform a simple membership request
-  Future<bool> _simpleMembershipRequest(int groupID, String uri) async =>
-      (await (APIRequest(uri: uri, needLogin: true)..addInt("id", groupID))
+  Future<bool> _simpleMembershipRequest(int groupID, String uri,
+          {Map<String, String> args}) async =>
+      (await (APIRequest(uri: uri, needLogin: true)
+                ..addInt("id", groupID)
+                ..addArgs(args == null ? Map() : args))
               .exec())
           .isOK;
 
@@ -118,6 +121,12 @@ class GroupsHelper {
   Future<bool> sendRequest(int groupID) async =>
       _simpleMembershipRequest(groupID, "groups/send_request");
 
+  /// Respond to a group membership invitation
+  Future<bool> respondInvitation(int groupID, bool accept) async =>
+      _simpleMembershipRequest(groupID, "groups/respond_invitation", args: {
+        "accept": accept ? "true" : "false",
+      });
+
   /// Turn an API entry into a group object
   Group _getGroupFromAPI(Map<String, dynamic> map) {
     return Group(
diff --git a/lib/models/api_request.dart b/lib/models/api_request.dart
index 0cc9c15..f268c3d 100644
--- a/lib/models/api_request.dart
+++ b/lib/models/api_request.dart
@@ -31,6 +31,8 @@ class APIRequest {
 
   void addFile(String name, File file) => files[name] = file;
 
+  void addArgs(Map<String, String> newArgs) => args.addAll(newArgs);
+
   /// Execute the request
   Future<APIResponse> exec() async => APIHelper().exec(this);
 
diff --git a/lib/ui/widgets/group_membership_widget.dart b/lib/ui/widgets/group_membership_widget.dart
index 4daf1da..0f69569 100644
--- a/lib/ui/widgets/group_membership_widget.dart
+++ b/lib/ui/widgets/group_membership_widget.dart
@@ -43,8 +43,8 @@ class _GroupMembershipWidgetState extends SafeState<GroupMembershipWidget> {
         return Text(tr("Member"));
 
       case GroupMembershipLevel.INVITED:
-        // TODO: Handle this case.
-        break;
+        return _buildInvitedState();
+
       case GroupMembershipLevel.PENDING:
         return _buildPendingState();
 
@@ -53,6 +53,49 @@ class _GroupMembershipWidgetState extends SafeState<GroupMembershipWidget> {
     }
   }
 
+  /// Build invited state
+  Widget _buildInvitedState() {
+    return RichText(
+      text: TextSpan(children: [
+        WidgetSpan(
+            child: Icon(Icons.info_outline, size: 12),
+            alignment: PlaceholderAlignment.middle),
+        TextSpan(text: " " + tr("Invited") + " "),
+        TextSpan(
+            text: tr("Accept"),
+            style: TextStyle(color: Colors.green),
+            recognizer: TapGestureRecognizer()
+              ..onTap = () => _respondInvitation(true)),
+        TextSpan(text: "  "),
+        TextSpan(
+            text: tr("Reject"),
+            style: TextStyle(color: Colors.red),
+            recognizer: TapGestureRecognizer()
+              ..onTap = () => _respondInvitation(false)),
+      ]),
+    );
+  }
+
+  /// Respond to an invitation
+  void _respondInvitation(bool accept) async {
+    if (!accept &&
+        !await showConfirmDialog(
+            context: context,
+            message: tr("Do you really want to reject this invitation?")))
+      return;
+
+    if (!await GroupsHelper().respondInvitation(_id, accept))
+      showSimpleSnack(context, tr("Could not respond to your invitation!"));
+    else {
+      // Refresh state
+      group.membershipLevel =
+          accept ? GroupMembershipLevel.MEMBER : GroupMembershipLevel.VISITOR;
+      this.setState(() {});
+
+      if (this.widget.onUpdated != null) this.widget.onUpdated();
+    }
+  }
+
   /// Build pending state
   Widget _buildPendingState() {
     return RichText(