diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 4a3a07d2..3bfc303f 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -247,7 +247,7 @@ class BaseDefinition(object):
 
         signature_text = '\n'.join(
             signature.to_string()
-            for signature in self._get_signatures()
+            for signature in self._get_signatures(for_docstring=True)
         )
         if signature_text and doc:
             return signature_text + '\n\n' + doc
@@ -484,7 +484,12 @@ class BaseDefinition(object):
         start_index = max(index - before, 0)
         return ''.join(lines[start_index:index + after + 1])
 
-    def _get_signatures(self):
+    def _get_signatures(self, for_docstring=False):
+        if for_docstring and self.type == 'statement' and not self.is_stub():
+            # For docstrings we don't resolve signatures if they are simple
+            # statements and not stubs. This is a speed optimization.
+            return []
+
         names = convert_names([self._name], prefer_stubs=True)
         return [sig for name in names for sig in name.infer().get_signatures()]
 
diff --git a/test/test_api/test_documentation.py b/test/test_api/test_documentation.py
index 0f5e933c..c59bd7f9 100644
--- a/test/test_api/test_documentation.py
+++ b/test/test_api/test_documentation.py
@@ -59,7 +59,7 @@ def test_help_no_returns(Script, code, kwargs):
         ('X.x', 'Yeah '),
         ('X().x', 'Yeah '),
         ('X.y', 'f g '),
-        ('X.z', '<lambda>(x)'),
+        ('X.z', ''),
     ]
 )
 def test_attribute_docstrings(goto_or_help, expected_doc, to_execute):
diff --git a/test/test_inference/test_docstring.py b/test/test_inference/test_docstring.py
index 0d85104d..8321d504 100644
--- a/test/test_inference/test_docstring.py
+++ b/test/test_inference/test_docstring.py
@@ -76,7 +76,7 @@ def test_multiple_docstrings(Script):
     x = func
     '''Docstring of `x`.'''
     x""").help()
-    assert d.docstring() == 'func()\n\nDocstring of `x`.'
+    assert d.docstring() == 'Docstring of `x`.'
 
 
 def test_completion(Script):
diff --git a/test/test_inference/test_gradual/test_stub_loading.py b/test/test_inference/test_gradual/test_stub_loading.py
index 12f2499a..7d62a24c 100644
--- a/test/test_inference/test_gradual/test_stub_loading.py
+++ b/test/test_inference/test_gradual/test_stub_loading.py
@@ -27,8 +27,7 @@ def test_find_stubs_infer(ScriptInStubFolder, code, expected):
     assert [d.name for d in defs] == expected
 
 
-func_without_stub_sig = 'func_without_stub(a)'
-func_without_stub_doc = func_without_stub_sig + '\n\nnostubdoc'
+func_without_stub_doc = 'func_without_stub(a)\n\nnostubdoc'
 func_with_stub_doc = 'func_with_stub(b: int) -> float\n\nwithstubdoc'
 
 
@@ -38,16 +37,16 @@ func_with_stub_doc = 'func_with_stub(b: int) -> float\n\nwithstubdoc'
         ('from with_python import python_only', ''),
         ('from with_python import both', ''),
 
-        ('import with_python; with_python.func_without_stub', func_without_stub_sig),
+        ('import with_python; with_python.func_without_stub', ''),
         ('import with_python.module; with_python.module.func_without_stub', func_without_stub_doc),
         ('from with_python import module; module.func_without_stub', func_without_stub_doc),
         ('from with_python.module import func_without_stub', func_without_stub_doc),
         ('from with_python.module import func_without_stub as f; f', func_without_stub_doc),
         ('from with_python.module import func_without_stub; func_without_stub',
          func_without_stub_doc),
-        ('from with_python import func_without_stub', func_without_stub_sig),
-        ('from with_python import func_without_stub as f; f', func_without_stub_sig),
-        ('from with_python import func_without_stub; func_without_stub', func_without_stub_sig),
+        ('from with_python import func_without_stub', ''),
+        ('from with_python import func_without_stub as f; f', ''),
+        ('from with_python import func_without_stub; func_without_stub', ''),
 
         ('import with_python; with_python.func_with_stub', func_with_stub_doc),
         ('import with_python.module; with_python.module.func_with_stub', func_with_stub_doc),