diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index f75be3f71ad..f0e543319c3 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -1630,6 +1630,13 @@ byte-optimize-append
             ;; (append X) -> X
             ((null newargs) arg)
 
+            ;; (append '(X...) ... '(Y...)) -> '(X... Y...)
+            ((and (eq (car-safe arg) 'quote)
+                  (cl-loop for newarg in newargs
+                           always (and (eq (car-safe newarg) 'quote)
+                                       (proper-list-p (cadr newarg)))))
+             `',(apply #'append (mapcar #'cadr (nreverse (cons arg newargs)))))
+
             ;; (append ... (list Xs...) nil) -> (append ... (list Xs...))
             ((and (null arg) (eq (car-safe prev) 'list))
              (cons (car form) (nreverse newargs)))