diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4546,10 +4546,15 @@
     if not (all or pats or show or mark or unmark):
         raise error.Abort(_('no files or directories specified'),
                          hint=('use --all to re-merge all unresolved files'))
+
     if mark and confirm and not pats:
         if ui.promptchoice(_(b'mark all unresolved files as resolved (yn)?'
                              b'$$ &Yes $$ &No')):
             raise error.Abort(_('user quit'))
+    if unmark and confirm and not pats:
+        if ui.promptchoice(_(b'mark all resolved files as unresolved (yn)?'
+                             b'$$ &Yes $$ &No')):
+            raise error.Abort(_('user quit'))
 
     if show:
         ui.pager('resolve')
diff --git a/tests/test-resolve.t b/tests/test-resolve.t
--- a/tests/test-resolve.t
+++ b/tests/test-resolve.t
@@ -557,6 +557,35 @@
   R emp2
   R emp3
 
+Test that commands.resolve.confirm respect --unmark option (only when no patterns args are given):
+===============================================================================================
+
+  $ hg resolve -u emp1
+
+  $ hg resolve -l
+  U emp1
+  R emp2
+  R emp3
+
+  $ hg resolve -u << EOF
+  > n
+  > EOF
+  mark all resolved files as unresolved (yn)? n
+  abort: user quit
+  [255]
+
+  $ hg resolve -m << EOF
+  > y
+  > EOF
+  mark all unresolved files as resolved (yn)? y
+  (no more unresolved files)
+  continue: hg rebase --continue
+
+  $ hg resolve -l
+  R emp1
+  R emp2
+  R emp3
+
   $ hg rebase --abort
   rebase aborted
   $ cd ..