diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -967,10 +967,7 @@ class queue:
             self.ui.write("No patches applied\n")
             return
         qp = self.qparents(repo, top)
-        if opts.get('git'):
-            self.diffopts().git = True
-        if opts.get('unified') is not None:
-            self.diffopts().context = opts['unified']
+        self._diffopts = patch.diffopts(self.ui, opts)
         self.printdiff(repo, qp, files=pats, opts=opts)
 
     def refresh(self, repo, pats=None, **opts):
@@ -2355,10 +2352,8 @@ cmdtable = {
          _('hg qcommit [OPTION]... [FILE]...')),
     "^qdiff":
         (diff,
-         [('g', 'git', None, _('use git extended diff format')),
-          ('U', 'unified', 3, _('number of lines of context to show')),
-         ] + commands.walkopts,
-         _('hg qdiff [-I] [-X] [-U NUM] [-g] [FILE]...')),
+         commands.diffopts + commands.diffopts2 + commands.walkopts,
+         _('hg qdiff [OPTION]... [FILE]...')),
     "qdelete|qremove|qrm":
         (delete,
          [('k', 'keep', None, _('keep patch file')),
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2932,6 +2932,23 @@ logopts = [
     ('M', 'no-merges', None, _('do not show merges')),
 ] + templateopts
 
+diffopts = [
+    ('a', 'text', None, _('treat all files as text')),
+    ('g', 'git', None, _('use git extended diff format')),
+    ('', 'nodates', None, _("don't include dates in diff headers"))
+]
+
+diffopts2 = [
+    ('p', 'show-function', None, _('show which function each change is in')),
+    ('w', 'ignore-all-space', None,
+     _('ignore white space when comparing lines')),
+    ('b', 'ignore-space-change', None,
+     _('ignore changes in the amount of white space')),
+    ('B', 'ignore-blank-lines', None,
+     _('ignore changes whose lines are all blank')),
+    ('U', 'unified', '', _('number of lines of context to show'))
+]
+
 table = {
     "^add": (add, walkopts + dryrunopts, _('hg add [OPTION]... [FILE]...')),
     "addremove":
@@ -3071,29 +3088,14 @@ table = {
     "debugwalk": (debugwalk, walkopts, _('hg debugwalk [OPTION]... [FILE]...')),
     "^diff":
         (diff,
-         [('r', 'rev', [], _('revision')),
-          ('a', 'text', None, _('treat all files as text')),
-          ('p', 'show-function', None,
-           _('show which function each change is in')),
-          ('g', 'git', None, _('use git extended diff format')),
-          ('', 'nodates', None, _("don't include dates in diff headers")),
-          ('w', 'ignore-all-space', None,
-           _('ignore white space when comparing lines')),
-          ('b', 'ignore-space-change', None,
-           _('ignore changes in the amount of white space')),
-          ('B', 'ignore-blank-lines', None,
-           _('ignore changes whose lines are all blank')),
-          ('U', 'unified', '',
-           _('number of lines of context to show'))
-         ] + walkopts,
+         [('r', 'rev', [], _('revision'))
+         ] + diffopts + diffopts2 + walkopts,
          _('hg diff [OPTION]... [-r REV1 [-r REV2]] [FILE]...')),
     "^export":
         (export,
          [('o', 'output', '', _('print output to file with formatted name')),
-          ('a', 'text', None, _('treat all files as text')),
-          ('g', 'git', None, _('use git extended diff format')),
-          ('', 'nodates', None, _("don't include dates in diff headers")),
-          ('', 'switch-parent', None, _('diff against the second parent'))],
+          ('', 'switch-parent', None, _('diff against the second parent'))
+          ] + diffopts,
          _('hg export [OPTION]... [-o OUTFILESPEC] REV...')),
     "grep":
         (grep,
diff --git a/tests/test-help.out b/tests/test-help.out
--- a/tests/test-help.out
+++ b/tests/test-help.out
@@ -201,9 +201,9 @@ options:
 
  -r --rev                  revision
  -a --text                 treat all files as text
- -p --show-function        show which function each change is in
  -g --git                  use git extended diff format
     --nodates              don't include dates in diff headers
+ -p --show-function        show which function each change is in
  -w --ignore-all-space     ignore white space when comparing lines
  -b --ignore-space-change  ignore changes in the amount of white space
  -B --ignore-blank-lines   ignore changes whose lines are all blank
diff --git a/tests/test-mq-qdiff b/tests/test-mq-qdiff
--- a/tests/test-mq-qdiff
+++ b/tests/test-mq-qdiff
@@ -25,3 +25,35 @@ hg qdiff | sed -e "s/\(+++ [a-zA-Z0-9_/.
 echo % qdiff dirname
 hg qdiff . | sed -e "s/\(+++ [a-zA-Z0-9_/.-]*\).*/\1/" \
                  -e "s/\(--- [a-zA-Z0-9_/.-]*\).*/\1/"
+
+echo % qdiff filename
+hg qdiff --nodates base
+
+echo % revert
+hg revert -a
+
+echo % qpop
+hg qpop
+
+echo % qdelete mqbase
+hg qdelete mqbase
+
+echo % commit 2
+printf '1\n2\n3\n4\nhello world\ngoodbye world\n7\n8\n9\n' > lines
+hg ci -Amlines -d '2 0'
+
+echo % qnew 2
+hg qnew -mmqbase2 mqbase2
+printf '\n\n1\n2\n3\n4\nhello  world\n     goodbye world\n7\n8\n9\n' > lines
+
+echo % qdiff -U 1
+hg qdiff --nodates -U 1
+
+echo % qdiff -b
+hg qdiff --nodates -b
+
+echo % qdiff -U 1 -B
+hg qdiff --nodates -U 1 -B
+
+echo qdiff -w
+hg qdiff --nodates -w
diff --git a/tests/test-mq-qdiff.out b/tests/test-mq-qdiff.out
--- a/tests/test-mq-qdiff.out
+++ b/tests/test-mq-qdiff.out
@@ -17,3 +17,71 @@ diff -r 67e992f2c4f3 base
 @@ -1,1 +1,1 @@
 -base
 +patched
+% qdiff filename
+diff -r 67e992f2c4f3 base
+--- a/base
++++ b/base
+@@ -1,1 +1,1 @@
+-base
++patched
+% revert
+% qpop
+Patch queue now empty
+% qdelete mqbase
+% commit 2
+adding lines
+% qnew 2
+% qdiff -U 1
+diff -r 35fb829491c1 lines
+--- a/lines
++++ b/lines
+@@ -1,1 +1,3 @@
++
++
+ 1
+@@ -4,4 +6,4 @@
+ 4
+-hello world
+-goodbye world
++hello  world
++     goodbye world
+ 7
+% qdiff -b
+diff -r 35fb829491c1 lines
+--- a/lines
++++ b/lines
+@@ -1,9 +1,11 @@
++
++
+ 1
+ 2
+ 3
+ 4
+-hello world
+-goodbye world
++hello  world
++     goodbye world
+ 7
+ 8
+ 9
+% qdiff -U 1 -B
+diff -r 35fb829491c1 lines
+--- a/lines
++++ b/lines
+@@ -4,4 +6,4 @@
+ 4
+-hello world
+-goodbye world
++hello  world
++     goodbye world
+ 7
+qdiff -w
+diff -r 35fb829491c1 lines
+--- a/lines
++++ b/lines
+@@ -1,3 +1,5 @@
++
++
+ 1
+ 2
+ 3