diff --git a/Doc/library/inspect.rst b/Doc/library/inspect.rst
--- a/Doc/library/inspect.rst
+++ b/Doc/library/inspect.rst
@@ -652,10 +652,9 @@
 
    .. attribute:: BoundArguments.arguments
 
-      An ordered, mutable mapping (:class:`collections.OrderedDict`) of
-      parameters' names to arguments' values.  Contains only explicitly bound
-      arguments.  Changes in :attr:`arguments` will reflect in :attr:`args` and
-      :attr:`kwargs`.
+      A mutable mapping of parameters' names to arguments' values.  Contains
+      only explicitly bound arguments.  Changes in :attr:`arguments` will
+      reflect in :attr:`args` and :attr:`kwargs`.
 
       Should be used in conjunction with :attr:`Signature.parameters` for any
       argument processing purposes.
diff --git a/Lib/inspect.py b/Lib/inspect.py
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2265,8 +2265,8 @@
 
     Has the following public attributes:
 
-    * arguments : OrderedDict
-        An ordered mutable mapping of parameters' names to arguments' values.
+    * arguments : dict
+        A mutable mapping of parameters' names to arguments' values.
         Does not contain arguments' default values.
     * signature : Signature
         The Signature object that created this instance.
@@ -2565,7 +2565,7 @@
     def _bind(self, args, kwargs, *, partial=False):
         """Private method. Don't use directly."""
 
-        arguments = OrderedDict()
+        arguments = {}
 
         parameters = iter(self.parameters.values())
         parameters_ex = ()
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -2997,9 +2997,9 @@
         ba = sig.bind(10, 20, b=30, c=40, args=50, kwargs=60)
         # we won't have 'z' argument in the bound arguments object, as we didn't
         # pass it to the 'bind'
-        self.assertEqual(tuple(ba.arguments.items()),
-                         (('a', 10), ('args', (20,)), ('b', 30),
-                          ('kwargs', {'c': 40, 'args': 50, 'kwargs': 60})))
+        self.assertEqual(ba.arguments,
+                         {'a': 10, 'args': (20,), 'b': 30,
+                          'kwargs': {'c': 40, 'args': 50, 'kwargs': 60}})
         self.assertEqual(ba.kwargs,
                          {'b': 30, 'c': 40, 'args': 50, 'kwargs': 60})
         self.assertEqual(ba.args, (10, 20))