diff --git a/lisp/international/quail.el b/lisp/international/quail.el
index 1bbbb174d49..c2ae44bb48f 100644
--- a/lisp/international/quail.el
+++ b/lisp/international/quail.el
@@ -1330,7 +1330,9 @@ If STR has `advice' text property, append the following special event:
 (defvar quail-conversion-str nil)
 
 (defun quail-input-method (key)
-  (if (or buffer-read-only
+  (if (or (and buffer-read-only
+	       (not (or inhibit-read-only
+			(get-char-property (point) 'inhibit-read-only))))
 	  (and overriding-terminal-local-map
                ;; If the overriding map is `universal-argument-map', that
                ;; must mean the user has pressed 'C-u KEY'.  If KEY has a