diff --git a/Lib/tkinter/__init__.py b/Lib/tkinter/__init__.py
index ee2415d..4726eff 100644
--- a/Lib/tkinter/__init__.py
+++ b/Lib/tkinter/__init__.py
@@ -2283,7 +2283,7 @@ class BaseWidget(Misc):
         if kw:
             cnf = _cnfmerge((cnf, kw))
         self.widgetName = widgetName
-        BaseWidget._setup(self, master, cnf)
+        self._setup(master, cnf)
         if self._tclCommands is None:
             self._tclCommands = []
         classes = [(k, v) for k, v in cnf.items() if isinstance(k, type)]
@@ -2638,6 +2638,12 @@ class Checkbutton(Widget):
         selectcolor, selectimage, state, takefocus, text, textvariable,
         underline, variable, width, wraplength."""
         Widget.__init__(self, master, 'checkbutton', cnf, kw)
+
+    def _setup(self, master, cnf):
+        super()._setup(master, cnf)
+        if 'variable' not in cnf:
+            cnf['variable'] = '%s-%d' % (self._name, id(self))
+
     def deselect(self):
         """Put the button in off-state."""
         self.tk.call(self._w, 'deselect')
diff --git a/Lib/tkinter/dialog.py b/Lib/tkinter/dialog.py
index f61c5f7..c2c10fa 100644
--- a/Lib/tkinter/dialog.py
+++ b/Lib/tkinter/dialog.py
@@ -10,7 +10,7 @@ class Dialog(Widget):
     def __init__(self, master=None, cnf={}, **kw):
         cnf = _cnfmerge((cnf, kw))
         self.widgetName = '__dialog__'
-        Widget._setup(self, master, cnf)
+        self._setup(master, cnf)
         self.num = self.tk.getint(
                 self.tk.call(
                       'tk_dialog', self._w,
diff --git a/Lib/tkinter/test/test_tkinter/test_widgets.py b/Lib/tkinter/test/test_tkinter/test_widgets.py
index 81b52ea..48f5827 100644
--- a/Lib/tkinter/test/test_tkinter/test_widgets.py
+++ b/Lib/tkinter/test/test_tkinter/test_widgets.py
@@ -212,6 +212,19 @@ class CheckbuttonTest(AbstractLabelTest, unittest.TestCase):
         widget = self.create()
         self.checkParams(widget, 'onvalue', 1, 2.3, '', 'any string')
 
+    def test_unique_variables(self):
+        frames = []
+        buttons = []
+        for i in range(2):
+            f = tkinter.Frame(self.root)
+            f.pack()
+            frames.append(f)
+            for j in 'AB':
+                b = tkinter.Checkbutton(f, text=j)
+                b.pack()
+                buttons.append(b)
+        variables = [str(b['variable']) for b in buttons]
+        self.assertEqual(len(set(variables)), 4, variables)
 
 @add_standard_options(StandardOptionsTests)
 class RadiobuttonTest(AbstractLabelTest, unittest.TestCase):
diff --git a/Lib/tkinter/tix.py b/Lib/tkinter/tix.py
index d9c097a..b08037f 100644
--- a/Lib/tkinter/tix.py
+++ b/Lib/tkinter/tix.py
@@ -303,7 +303,7 @@ class TixWidget(tkinter.Widget):
                 del cnf[k]
 
         self.widgetName = widgetName
-        Widget._setup(self, master, cnf)
+        self._setup(master, cnf)
 
         # If widgetName is None, this is a dummy creation call where the
         # corresponding Tk widget has already been created by Tix