diff --git a/jedi/evaluate/context/klass.py b/jedi/evaluate/context/klass.py
index acf68b67..f07ee125 100644
--- a/jedi/evaluate/context/klass.py
+++ b/jedi/evaluate/context/klass.py
@@ -38,7 +38,7 @@ py__doc__()                            Returns the docstring for a context.
 """
 from jedi import debug
 from jedi._compatibility import use_metaclass
-from jedi.parser_utils import get_parent_scope
+from jedi.parser_utils import get_cached_parent_scope
 from jedi.evaluate.cache import evaluator_method_cache, CachedMetaClass, \
     evaluator_method_generator_cache
 from jedi.evaluate import compiled
@@ -106,7 +106,7 @@ class ClassFilter(ParserTreeFilter):
         while node is not None:
             if node == self._parser_scope or node == self.context:
                 return True
-            node = get_parent_scope(node)
+            node = get_cached_parent_scope(self._used_names, node)
         return False
 
     def _access_possible(self, name):
diff --git a/jedi/evaluate/filters.py b/jedi/evaluate/filters.py
index 29b55517..a65b3c49 100644
--- a/jedi/evaluate/filters.py
+++ b/jedi/evaluate/filters.py
@@ -11,13 +11,13 @@ from jedi._compatibility import use_metaclass
 from jedi.evaluate import flow_analysis
 from jedi.evaluate.base_context import ContextSet, Context, ContextWrapper, \
     LazyContextWrapper
-from jedi.parser_utils import get_parent_scope
+from jedi.parser_utils import get_cached_parent_scope
 from jedi.evaluate.utils import to_list
-from jedi.evaluate.cache import evaluator_function_cache
 from jedi.evaluate.names import TreeNameDefinition, ParamName, AbstractNameDefinition
 
 _definition_name_cache = weakref.WeakKeyDictionary()
 
+
 class AbstractFilter(object):
     _until_position = None
 
@@ -75,8 +75,6 @@ class AbstractUsedNamesFilter(AbstractFilter):
         self.context = context
 
     def get(self, name):
-        #print(self, self.context, name, type(self).__name__)
-        #import traceback, sys; traceback.print_stack(file=sys.stdout)
         return self._convert_names(self._filter(
             _get_definition_names(self._used_names, name)
         ))
@@ -124,7 +122,7 @@ class ParserTreeFilter(AbstractUsedNamesFilter):
         if parent.type == 'trailer':
             return False
         base_node = parent if parent.type in ('classdef', 'funcdef') else name
-        return get_parent_scope(base_node) == self._parser_scope
+        return get_cached_parent_scope(self._used_names, base_node) == self._parser_scope
 
     def _check_flows(self, names):
         for name in sorted(names, key=lambda name: name.start_pos, reverse=True):
diff --git a/jedi/parser_utils.py b/jedi/parser_utils.py
index 8d02c313..dcbd802c 100644
--- a/jedi/parser_utils.py
+++ b/jedi/parser_utils.py
@@ -1,6 +1,7 @@
 import re
 import textwrap
 from inspect import cleandoc
+from weakref import WeakKeyDictionary
 
 from parso.python import tree
 from parso.cache import parser_cache
@@ -226,6 +227,23 @@ def is_scope(node):
     return t in ('file_input', 'classdef', 'funcdef', 'lambdef', 'sync_comp_for')
 
 
+def _get_parent_scope_cache(func):
+    cache = WeakKeyDictionary()
+
+    def wrapper(used_names, node, include_flows=False):
+        try:
+            for_module = cache[used_names]
+        except KeyError:
+            for_module = cache[used_names] = {}
+
+        try:
+            return for_module[node]
+        except KeyError:
+            result = for_module[node] = func(node, include_flows)
+            return result
+    return wrapper
+
+
 def get_parent_scope(node, include_flows=False):
     """
     Returns the underlying scope.
@@ -251,6 +269,9 @@ def get_parent_scope(node, include_flows=False):
     return scope
 
 
+get_cached_parent_scope = _get_parent_scope_cache(get_parent_scope)
+
+
 def get_cached_code_lines(grammar, path):
     """
     Basically access the cached code lines in parso. This is not the nicest way