diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 15eab0a4de5..2c7c6dae755 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -2850,8 +2850,10 @@ implementation will be used."
 		 ;; command.
 		 (heredoc (and (stringp program)
 			       (string-match-p "sh$" program)
+			       (= (length args) 2)
 			       (string-equal "-c" (car args))
-			       (= (length args) 2)))
+			       ;; Don't if there is a string.
+			       (not (string-match-p "'\\|\"" (cadr args)))))
 		 ;; When PROGRAM is nil, we just provide a tty.
 		 (args (if (not heredoc) args
 			 (let ((i 250))