diff --git a/lisp/tab-bar.el b/lisp/tab-bar.el
index 2604955224..82f3ca2385 100644
--- a/lisp/tab-bar.el
+++ b/lisp/tab-bar.el
@@ -334,6 +334,18 @@ tab-bar-tab-name-function
   :group 'tab-bar
   :version "27.1")
 
+(defcustom tab-bar-tab-name-format-function nil
+  "Function to format a tab name.
+Function get one argument, the tab name, and should return
+the formatted tab name."
+  :type 'function
+  :initialize 'custom-initialize-default
+  :set (lambda (sym val)
+         (set-default sym val)
+         (force-mode-line-update))
+  :group 'tab-bar
+  :version "28.1")
+
 (defun tab-bar-tab-name-current ()
   "Generate tab name from the buffer of the selected window."
   (buffer-name (window-buffer (minibuffer-selected-window))))
@@ -433,8 +445,9 @@ tab-bar-make-keymap-1
           ((eq (car tab) 'current-tab)
            `((current-tab
               menu-item
-              ,(propertize (concat (if tab-bar-tab-hints (format "%d " i) "")
-                                   (alist-get 'name tab)
+              ,(propertize (concat (funcall (or tab-bar-tab-name-format-function 'identity)
+                                            (concat (if tab-bar-tab-hints (format "%d " i) "")
+                                                    (alist-get 'name tab)))
                                    (or (and tab-bar-close-button-show
                                             (not (eq tab-bar-close-button-show
                                                      'non-selected))
@@ -445,8 +458,9 @@ tab-bar-make-keymap-1
           (t
            `((,(intern (format "tab-%i" i))
               menu-item
-              ,(propertize (concat (if tab-bar-tab-hints (format "%d " i) "")
-                                   (alist-get 'name tab)
+              ,(propertize (concat (funcall (or tab-bar-tab-name-format-function 'identity)
+                                            (concat (if tab-bar-tab-hints (format "%d " i) "")
+                                                    (alist-get 'name tab)))
                                    (or (and tab-bar-close-button-show
                                             (not (eq tab-bar-close-button-show
                                                      'selected))