diff --git a/qcore/caching.py b/qcore/caching.py
index ec9cf9d..51be2bf 100644
--- a/qcore/caching.py
+++ b/qcore/caching.py
@@ -331,6 +331,9 @@ def get_args_tuple(args, kwargs, arg_names, kwargs_defaults):
             else:
                 args_list.append(kwargs[arg_name])
             args_len += 1
+        remaining_keys = sorted([k for k in kwargs if k not in arg_names])
+        for k in remaining_keys:
+            args_list.append((k, kwargs[k]))
     except KeyError as e:
         raise TypeError("Missing argument %r" % (e.args[0],))
     return tuple(args_list)
diff --git a/qcore/tests/test_caching.py b/qcore/tests/test_caching.py
index eaada00..2059695 100644
--- a/qcore/tests/test_caching.py
+++ b/qcore/tests/test_caching.py
@@ -363,6 +363,11 @@ def with_kwargs(self, x=1, y=2, z=3):
         self.x += x + y + z
         return self.x
 
+    @cached_per_instance()
+    def with_variable_kwargs(self, **kwargs):
+        self.x += sum(kwargs.values())
+        return self.x
+
 
 def test_cached_per_instance():
     get_x_cache = TestClass.get_x.__cached_per_instance_cache__
@@ -413,6 +418,17 @@ def test_cached_per_instance():
     assert_eq(0, len(get_x_cache), extra=repr(get_x_cache))
     assert_eq(0, len(with_kwargs_cache), extra=repr(with_kwargs_cache))
 
+    object3 = TestClass(0)
+    assert_eq(0, object3.x)
+    object3.with_variable_kwargs(k1=2)
+    assert_eq(2, object3.x)
+    object3.with_variable_kwargs(k1=2)
+    assert_eq(2, object3.x)
+    object3.with_variable_kwargs(k2=2)
+    assert_eq(4, object3.x)
+    object3.with_variable_kwargs(k1=2, k2=2)
+    assert_eq(8, object3.x)
+
 
 class PickleTestClass(object):
     @cached_per_instance()