diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 6c7a0d2..d8596aa 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -494,9 +494,13 @@ removes itself from that hook."
       (forward-line 1)
       (while (progn
 	       (forward-char 2)
-	       (if (= (following-char) ?\()
-		   (forward-sexp 1)
-		 (forward-sexp 2))
+	       (cond ((debugger--locals-visible-p)
+		      (goto-char (next-single-char-property-change
+				  (1+ (point)) 'debugger-locals-visible-p)))
+		     ((= (following-char) ?\()
+		      (forward-sexp 1))
+		     (t
+		      (forward-sexp 2)))
 	       (forward-line 1)
 	       (<= (point) opoint))
 	(if (looking-at " *;;;")
@@ -558,6 +562,89 @@ The environment used is the one when entering the activation frame at point."
             (prin1 val t)
           (let ((str (eval-expression-print-format val)))
             (if str (princ str t))))))))
+
+(defun debugger--backtrace-base ()
+  "Return the function name that marks the top of the backtrace.
+See `backtrace-frame'."
+  (cond ((eq 'debug--implement-debug-on-entry
+	     (cadr (backtrace-frame 1 'debug)))
+	 'debug--implement-debug-on-entry)
+	(t 'debug)))
+
+(defun debugger--locals-visible-p ()
+  "Are the local variables of the current stack frame visible?"
+  (save-excursion
+    (move-to-column 2)
+    (get-text-property (point) 'debugger-locals-visible-p)))
+
+(defun debugger--insert-locals (locals)
+  "Insert the local variables LOCALS at point."
+  ;; A bit messy because we need to deal with lexical frames, i.e.
+  ;; the ones with the magic symbol 'internal-interpreter-environment.
+  (when (null locals)
+    (insert "\n    [no locals]"))
+  (dolist (s+v locals)
+    (let ((symbol (car s+v))
+	  (value (cdr s+v))
+	  (print-escape-newlines t)
+	  (insert (lambda (s v)
+		    (insert "\n    ")
+		    (prin1 s (current-buffer))
+		    (insert ": ")
+		    (prin1 v (current-buffer)))))
+      (cond ((string= (symbol-name symbol) "internal-interpreter-environment")
+	     (cond ((or (null value)
+			(and (null (cdr value))
+			     (symbol (car value))))
+		    (insert "\n    [no locals]"))
+		   (t
+		    (dolist (s+v value)
+		      (unless (symbolp s+v)
+			(let ((symbol (car s+v))
+			      (value (cdr s+v)))
+			  (funcall insert symbol value)))))))
+	    (t
+	     (funcall insert symbol value))))))
+
+(defun debugger--show-locals ()
+  "For the frame at point, insert locals and add text properties."
+  (let* ((nframe (debugger-frame-number 'skip-base))
+	 (base (debugger--backtrace-base))
+	 (locals (backtrace-locals nframe base))
+	 (inhibit-read-only t))
+    (save-excursion
+      (let ((start (progn
+		     (beginning-of-line)
+		     (skip-chars-forward " ")
+		     (point))))
+	(end-of-line)
+	(debugger--insert-locals locals)
+	(add-text-properties start (point) '(debugger-locals-visible-p t))))))
+
+(defun debugger--hide-locals ()
+  "Delete local variables and remove the text property."
+  (let* ((col (current-column))
+	 (end (progn
+		(move-to-column 2)
+		(next-single-char-property-change
+		 (point) 'debugger-locals-visible-p)))
+	 (start (previous-single-char-property-change
+		 end 'debugger-locals-visible-p))
+	 (inhibit-read-only t))
+    (goto-char start)
+    (end-of-line)
+    (remove-text-properties start end '(debugger-locals-visible-p))
+    (delete-region (point) end)
+    (move-to-column col)))
+
+(defun debugger-toggle-locals ()
+  "Show or hide local variables of the current stack frame."
+  (interactive)
+  (cond ((debugger--locals-visible-p)
+	 (debugger--hide-locals))
+	(t
+	 (debugger--show-locals))))
+
 
 (defvar debugger-mode-map
   (let ((map (make-keymap))
@@ -575,6 +662,7 @@ The environment used is the one when entering the activation frame at point."
     (define-key map "h" 'describe-mode)
     (define-key map "q" 'top-level)
     (define-key map "e" 'debugger-eval-expression)
+    (define-key map "t" 'debugger-toggle-locals)
     (define-key map " " 'next-line)
     (define-key map "R" 'debugger-record-expression)
     (define-key map "\C-m" 'debug-help-follow)
diff --git a/src/eval.c b/src/eval.c
index d3fcec5..a455d95 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3576,6 +3576,53 @@ NFRAMES and BASE specify the activation frame to use, as in `backtrace-frame'.
      from the debugger.  */
   return unbind_to (count, eval_sub (exp));
 }
+
+DEFUN ("backtrace-locals", Fbacktrace_locals, Sbacktrace_locals, 1, 2, NULL,
+       doc: /* Return names and values of local variables of a stack frame.
+NFRAMES and BASE specify the activation frame to use, as in `backtrace-frame'.
+The result is an alist. */)
+  (Lisp_Object nframes, Lisp_Object base)
+{
+  union specbinding *frame = get_backtrace_frame (nframes, base);
+  union specbinding *olderframe =
+    get_backtrace_frame (make_number (XFASTINT (nframes) + 1), base);
+  ptrdiff_t distance = specpdl_ptr - olderframe;
+  Lisp_Object result = Qnil;
+  eassert (distance >= 0);
+
+  if (!backtrace_p (frame))
+    error ("Activation frame not found!");
+  if (!backtrace_p (olderframe))
+    error ("Activation frame not found!");
+
+  /* move values to specpdl */
+  backtrace_eval_unrewind (distance);
+
+  /* grab values */
+  {
+    union specbinding *tmp = frame;
+    for (; tmp > olderframe; tmp--)
+      {
+	switch (tmp->kind)
+	  {
+	  case SPECPDL_LET:
+	  case SPECPDL_LET_DEFAULT:
+	  case SPECPDL_LET_LOCAL:
+	    {
+	      Lisp_Object sym = specpdl_symbol (tmp);
+	      Lisp_Object val = specpdl_old_value (tmp);
+	      result = Fcons (Fcons (sym, val), result);
+	    }
+	  }
+      }
+  }
+
+  /* restore values from specpdl to orignal place */
+  backtrace_eval_unrewind (-distance);
+
+  return result;
+}
+
 
 void
 mark_specpdl (void)
@@ -3824,6 +3871,7 @@ alist of active lexical bindings.  */);
   defsubr (&Sbacktrace);
   defsubr (&Sbacktrace_frame);
   defsubr (&Sbacktrace_eval);
+  defsubr (&Sbacktrace_locals);
   defsubr (&Sspecial_variable_p);
   defsubr (&Sfunctionp);
 }