diff --git a/Lib/inspect.py b/Lib/inspect.py
index b8a142232b88a0..53e96801d9137a 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -319,23 +319,21 @@ def isabstract(object):
 def getmembers(object, predicate=None):
     """Return all members of an object as (name, value) pairs sorted by name.
     Optionally, only return members that satisfy a given predicate."""
-    if isclass(object):
-        mro = (object,) + getmro(object)
-    else:
-        mro = ()
-    results = []
-    processed = set()
     names = dir(object)
-    # :dd any DynamicClassAttributes to the list of names if object is a class;
-    # this may result in duplicate entries if, for example, a virtual
-    # attribute with the same name as a DynamicClassAttribute exists
-    try:
+    if isclass(object):
+        mro = getmro(object)
+        # Add any DynamicClassAttributes to the list of names
+        # if object is a class;
+        # this may result in duplicate entries if, for example, a virtual
+        # attribute with the same name as a DynamicClassAttribute exists
         for base in object.__bases__:
             for k, v in base.__dict__.items():
                 if isinstance(v, types.DynamicClassAttribute):
                     names.append(k)
-    except AttributeError:
-        pass
+    else:
+        mro = ()
+    results = []
+    processed = set()
     for key in names:
         # First try to get the value via getattr.  Some descriptors don't
         # like calling their __get__ (see bug #1785), so fall back to
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index b9072e0137eb08..26a4bd037edd5e 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -1171,6 +1171,36 @@ class C(metaclass=M):
         attrs = [a[0] for a in inspect.getmembers(C)]
         self.assertNotIn('missing', attrs)
 
+    def test_getmembers_with_non_class(self):
+        name = '__inspect_dummy'
+        m = types.ModuleType(name)
+        m.__bases__ = None
+        attrs = [a[0] for a in inspect.getmembers(m)]
+        self.assertIn('__bases__', attrs)
+
+    def test_getmembers_with_custom_getattr(self):
+        class CustomGetattr(object):
+            def __getattr__(self, attr):
+                return None
+
+        CustomGetattr.__test__ = None
+        attrs = [a[0] for a in inspect.getmembers(CustomGetattr())]
+        self.assertIn('__test__', attrs)
+
+    def test_getmembers_with_dynamic_class_attribute(self):
+        class A:
+            @types.DynamicClassAttribute
+            def ham(self):
+                return 'eggs'
+        class B(A): pass
+        class C(B): pass
+
+        attrs = [b[0] for b in inspect.getmembers(B)]
+        self.assertIn('ham', attrs)
+        attrs = [c[0] for c in inspect.getmembers(C)]
+        self.assertIn('ham', attrs)
+
+
 class TestIsDataDescriptor(unittest.TestCase):
 
     def test_custom_descriptors(self):
diff --git a/Misc/NEWS.d/next/Library/2018-07-14-23-52-12.bpo-33668.7poHxA.rst b/Misc/NEWS.d/next/Library/2018-07-14-23-52-12.bpo-33668.7poHxA.rst
new file mode 100644
index 00000000000000..0776187becd0ed
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-07-14-23-52-12.bpo-33668.7poHxA.rst
@@ -0,0 +1 @@
+Fix :func:`inspect.getmembers` to traversing mro when the object is a class only.