diff --git a/emacs/notmuch-mua.el b/emacs/notmuch-mua.el
index 32e2e30b..d8ab822a 100644
--- a/emacs/notmuch-mua.el
+++ b/emacs/notmuch-mua.el
@@ -71,12 +71,15 @@ list."
 	    (push header message-hidden-headers)))
 	notmuch-mua-hidden-headers))
 
-(defun notmuch-mua-reply (query-string &optional sender)
+(defun notmuch-mua-reply (query-string &optional sender reply-all)
   (let (headers
 	body
 	(args '("reply")))
     (if notmuch-show-process-crypto
 	(setq args (append args '("--decrypt"))))
+    (if reply-all
+	(setq args (append args '("--reply-to=all")))
+      (setq args (append args '("--reply-to=sender"))))
     (setq args (append args (list query-string)))
     ;; This make assumptions about the output of `notmuch reply', but
     ;; really only that the headers come first followed by a blank
@@ -218,13 +221,13 @@ the From: address first."
 	(notmuch-mua-forward-message))
     (notmuch-mua-forward-message)))
 
-(defun notmuch-mua-new-reply (query-string &optional prompt-for-sender)
+(defun notmuch-mua-new-reply (query-string &optional prompt-for-sender reply-all)
   "Invoke the notmuch reply window."
   (interactive "P")
   (let ((sender
 	 (when prompt-for-sender
 	   (notmuch-mua-prompt-for-sender))))
-    (notmuch-mua-reply query-string sender)))
+    (notmuch-mua-reply query-string sender reply-all)))
 
 (defun notmuch-mua-send-and-exit (&optional arg)
   (interactive "P")
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 034db87e..9031b824 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -934,6 +934,7 @@ thread id.  If a prefix is given, crypto processing is toggled."
 	(define-key map "m" 'notmuch-mua-new-mail)
 	(define-key map "f" 'notmuch-show-forward-message)
 	(define-key map "r" 'notmuch-show-reply)
+	(define-key map "R" 'notmuch-show-reply-sender)
 	(define-key map "|" 'notmuch-show-pipe-message)
 	(define-key map "w" 'notmuch-show-save-attachments)
 	(define-key map "V" 'notmuch-show-view-raw-message)
@@ -1238,9 +1239,14 @@ any effects from previous calls to
       (notmuch-show-previous-message)))))
 
 (defun notmuch-show-reply (&optional prompt-for-sender)
-  "Reply to the current message."
+  "Reply to the sender and all recipients of the current message."
   (interactive "P")
-  (notmuch-mua-new-reply (notmuch-show-get-message-id) prompt-for-sender))
+  (notmuch-mua-new-reply (notmuch-show-get-message-id) prompt-for-sender t))
+
+(defun notmuch-show-reply-sender (&optional prompt-for-sender)
+  "Reply to the sender of the current message."
+  (interactive "P")
+  (notmuch-mua-new-reply (notmuch-show-get-message-id) prompt-for-sender nil))
 
 (defun notmuch-show-forward-message (&optional prompt-for-sender)
   "Forward the current message."
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 1e617752..9ac28887 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -214,6 +214,7 @@ For a mouse binding, return nil."
     (define-key map "p" 'notmuch-search-previous-thread)
     (define-key map "n" 'notmuch-search-next-thread)
     (define-key map "r" 'notmuch-search-reply-to-thread)
+    (define-key map "R" 'notmuch-search-reply-to-thread-sender)
     (define-key map "m" 'notmuch-mua-new-mail)
     (define-key map "s" 'notmuch-search)
     (define-key map "o" 'notmuch-search-toggle-order)
@@ -448,10 +449,16 @@ Complete list of currently available key bindings:
       (message "End of search results."))))
 
 (defun notmuch-search-reply-to-thread (&optional prompt-for-sender)
+  "Begin composing a reply-all to the entire current thread in a new buffer."
+  (interactive "P")
+  (let ((message-id (notmuch-search-find-thread-id)))
+    (notmuch-mua-new-reply message-id prompt-for-sender t)))
+
+(defun notmuch-search-reply-to-thread-sender (&optional prompt-for-sender)
   "Begin composing a reply to the entire current thread in a new buffer."
   (interactive "P")
   (let ((message-id (notmuch-search-find-thread-id)))
-    (notmuch-mua-new-reply message-id prompt-for-sender)))
+    (notmuch-mua-new-reply message-id prompt-for-sender nil)))
 
 (defun notmuch-call-notmuch-process (&rest args)
   "Synchronously invoke \"notmuch\" with the given list of arguments.