diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index 1d394511c96..6e89aa20435 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -940,7 +940,8 @@
 	 form)
 	 ;; The body is nil
 	((eq (car form) 'let)
-	 (append '(progn) (mapcar 'car (mapcar 'cdr (nth 1 form))) '(nil)))
+	 (append '(progn) (mapcar 'car-safe (mapcar 'cdr-safe (nth 1 form)))
+		 '(nil)))
 	(t
 	 (let ((binds (reverse (nth 1 form))))
 	   (list 'let* (reverse (cdr binds)) (nth 1 (car binds)) nil)))))