diff --git a/lisp/tab-bar.el b/lisp/tab-bar.el
index d2815c03ebf..e21367255a0 100644
--- a/lisp/tab-bar.el
+++ b/lisp/tab-bar.el
@@ -1227,7 +1227,9 @@ tab-bar-auto-width
                    ((< prev-width width)
                     (let* ((space (apply #'propertize " "
                                          (text-properties-at 0 name)))
-                           (ins-pos (- len (if close-p 1 0)))
+                           (ins-pos (- len (if close-p
+                                               (length tab-bar-close-button)
+                                             0)))
                            (prev-name name))
                       (while continue
                         (setq name (concat (substring name 0 ins-pos)