diff --git a/app/assets/javascripts/discourse/app/controllers/user-private-messages.js b/app/assets/javascripts/discourse/app/controllers/user-private-messages.js
index adef41e742e..8aae040a378 100644
--- a/app/assets/javascripts/discourse/app/controllers/user-private-messages.js
+++ b/app/assets/javascripts/discourse/app/controllers/user-private-messages.js
@@ -55,12 +55,11 @@ export default class extends Controller {
 
   @cached
   get messagesDropdownContent() {
+    const usernameLower = this.model.username_lower;
+
     const content = [
       {
-        id: this.router.urlFor(
-          "userPrivateMessages.user",
-          this.model.username_lower
-        ),
+        id: this.router.urlFor("userPrivateMessages.user", usernameLower),
         name: I18n.t("user.messages.inbox"),
       },
     ];
@@ -69,7 +68,7 @@ export default class extends Controller {
       content.push({
         id: this.router.urlFor(
           "userPrivateMessages.group",
-          this.model.username,
+          usernameLower,
           group.name
         ),
         name: group.name,
@@ -79,10 +78,7 @@ export default class extends Controller {
 
     if (this.pmTaggingEnabled) {
       content.push({
-        id: this.router.urlFor(
-          "userPrivateMessages.tags",
-          this.model.username_lower
-        ),
+        id: this.router.urlFor("userPrivateMessages.tags", usernameLower),
         name: I18n.t("user.messages.tags"),
         icon: "tags",
       });
@@ -90,7 +86,7 @@ export default class extends Controller {
 
     customUserNavMessagesDropdownRows.forEach((row) => {
       content.push({
-        id: this.router.urlFor(row.routeName, this.model.username_lower),
+        id: this.router.urlFor(row.routeName, usernameLower),
         name: row.name,
         icon: row.icon,
       });
diff --git a/app/assets/javascripts/discourse/tests/acceptance/user-private-messages-test.js b/app/assets/javascripts/discourse/tests/acceptance/user-private-messages-test.js
index 26dd52bbb95..043d913a19f 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/user-private-messages-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/user-private-messages-test.js
@@ -954,12 +954,28 @@ acceptance(
 acceptance(
   "User Private Messages - user with uppercase username",
   function (needs) {
-    needs.user();
+    needs.user({
+      groups: [{ id: 14, name: "awesome_group", has_messages: true }],
+    });
 
     needs.pretender((server, helper) => {
       const response = cloneJSON(userFixtures["/u/charlie.json"]);
       response.user.username = "chArLIe";
       server.get("/u/charlie.json", () => helper.response(response));
+
+      server.get(
+        "/topics/private-messages-group/:username/:group_name.json",
+        () => {
+          return helper.response({
+            topic_list: {
+              topics: [
+                { id: 1, posters: [] },
+                { id: 2, posters: [] },
+              ],
+            },
+          });
+        }
+      );
     });
 
     test("viewing inbox", async function (assert) {
@@ -971,5 +987,15 @@ acceptance(
         "menu defaults to Inbox"
       );
     });
+
+    test("viewing group inbox", async function (assert) {
+      await visit("/u/charlie/messages/group/awesome_group");
+
+      assert.strictEqual(
+        query(".user-nav-messages-dropdown .selected-name").textContent.trim(),
+        "awesome_group",
+        "dropdown menu displays the right group name"
+      );
+    });
   }
 );