diff --git a/lisp/org-macs.el b/lisp/org-macs.el
index 65a864758..ad1fab50b 100644
--- a/lisp/org-macs.el
+++ b/lisp/org-macs.el
@@ -43,6 +43,10 @@
   "Return the value of symbol VAR if it is bound, else nil."
   `(and (boundp (quote ,var)) ,var))
 
+(defun org-not-nil (v)
+  "Is V not nil, and also not the string \"nil\"?"
+  (and v (not (equal v "nil"))))
+
 (defmacro org-unmodified (&rest body)
   "Execute body without changing `buffer-modified-p'.
 Also, do not record undo information."
diff --git a/lisp/org.el b/lisp/org.el
index 21a14678d..7bb4f45d7 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -10881,7 +10881,7 @@ changes.  Such blocking occurs when:
 	(let* ((pos (point))
 	       (parent-pos (and (org-up-heading-safe) (point))))
 	  (if (not parent-pos) (throw 'dont-block t)) ; no parent
-	  (when (and (org-entry-get (point) "ORDERED")
+	  (when (and (org-not-nil (org-entry-get (point) "ORDERED"))
 		     (forward-line 1)
 		     (re-search-forward org-not-done-heading-regexp pos t))
 	    (throw 'dont-block nil))  ; block, there is an older sibling not done.
@@ -10893,7 +10893,7 @@ changes.  Such blocking occurs when:
 	    (setq pos (point))
 	    (setq parent-pos (and (org-up-heading-safe) (point)))
 	    (if (not parent-pos) (throw 'dont-block t)) ; no parent
-	    (when (and (org-entry-get (point) "ORDERED")
+	    (when (and (org-not-nil (org-entry-get (point) "ORDERED"))
 		       (forward-line 1)
 		       (re-search-forward org-not-done-heading-regexp pos t))
 	      (throw 'dont-block nil)))))))) ; block, older sibling not done.