diff --git a/CHANGELOG.md b/CHANGELOG.md
index c10900a99cf0..96464b7e5290 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* Fix bug in `compas.datastructures.AttributesView`.
+
 ### Removed
 
 
diff --git a/src/compas/datastructures/attributes.py b/src/compas/datastructures/attributes.py
index 00c4f3abf1b0..3426419b41ed 100644
--- a/src/compas/datastructures/attributes.py
+++ b/src/compas/datastructures/attributes.py
@@ -13,8 +13,8 @@
 ]
 
 
-class AttributeView(object):
-    """Mixin for attribute dict views."""
+class AttributeView(MutableMapping):
+    """Base class for attribute dict views."""
 
     def __init__(self, defaults, attr, custom_only=False):
         super(AttributeView, self).__init__()
@@ -29,7 +29,7 @@ def __str__(self):
         return "{" + ", ".join(s) + "}"
 
     def __len__(self):
-        return len(self.defaults)
+        return len(set(self.defaults).union(self.attr))
 
     def __getitem__(self, name):
         if name not in self.attr:
@@ -48,11 +48,12 @@ def __iter__(self):
             for name in self.attr:
                 yield name
         else:
-            for name in self.defaults:
+            names = set(self.defaults).union(self.attr)
+            for name in names:
                 yield name
 
 
-class NodeAttributeView(AttributeView, MutableMapping):
+class NodeAttributeView(AttributeView):
     """Mutable Mapping that provides a read/write view of the custom attributes of a node
     combined with the default attributes of all nodes."""
 
@@ -60,7 +61,7 @@ def __init__(self, defaults, attr, custom_only=False):
         super(NodeAttributeView, self).__init__(defaults, attr, custom_only)
 
 
-class VertexAttributeView(AttributeView, MutableMapping):
+class VertexAttributeView(AttributeView):
     """Mutable Mapping that provides a read/write view of the custom attributes of a vertex
     combined with the default attributes of all vertices."""
 
@@ -68,7 +69,7 @@ def __init__(self, defaults, attr, custom_only=False):
         super(VertexAttributeView, self).__init__(defaults, attr, custom_only)
 
 
-class EdgeAttributeView(AttributeView, MutableMapping):
+class EdgeAttributeView(AttributeView):
     """Mutable Mapping that provides a read/write view of the custom attributes of an edge
     combined with the default attributes of all edges."""
 
@@ -76,7 +77,7 @@ def __init__(self, defaults, attr, custom_only=False):
         super(EdgeAttributeView, self).__init__(defaults, attr, custom_only)
 
 
-class FaceAttributeView(AttributeView, MutableMapping):
+class FaceAttributeView(AttributeView):
     """Mutable Mapping that provides a read/write view of the custom attributes of a face
     combined with the default attributes of all faces."""
 
@@ -84,7 +85,7 @@ def __init__(self, defaults, attr, custom_only=False):
         super(FaceAttributeView, self).__init__(defaults, attr, custom_only)
 
 
-class CellAttributeView(AttributeView, MutableMapping):
+class CellAttributeView(AttributeView):
     """Mutable Mapping that provides a read/write view of the custom attributes of a cell
     combined with the default attributes of all faces."""
 
diff --git a/tests/compas/datastructures/test_mesh.py b/tests/compas/datastructures/test_mesh.py
index 9483a7c2bc50..2f9309e69f41 100644
--- a/tests/compas/datastructures/test_mesh.py
+++ b/tests/compas/datastructures/test_mesh.py
@@ -1,11 +1,12 @@
-# import pytest
-import os
-import compas
 import json
+import os
+
 import pytest
 
+import compas
 from compas.datastructures import Mesh
 from compas.datastructures import meshes_join_and_weld
+from compas.geometry import Box
 from compas.geometry import Polygon
 from compas.geometry import Translation
 
@@ -20,6 +21,12 @@ def cube():
     return Mesh.from_polyhedron(6)
 
 
+@pytest.fixture
+def box():
+    box = Box.from_width_height_depth(2, 2, 2)
+    return Mesh.from_shape(box)
+
+
 @pytest.fixture
 def hexagon():
     polygon = Polygon.from_sides_and_radius_xy(6, 1)
@@ -666,3 +673,14 @@ def test_faces_on_boundaries_triangleboundarychain(triangleboundarychain):
 # --------------------------------------------------------------------------
 # attributes
 # --------------------------------------------------------------------------
+
+def test_face_attributes_includes_all_defaults(box):
+    box.update_default_face_attributes({"attr1": "value1", "attr2": "value2"})
+
+    random_fkey = box.get_any_face()
+    assert sorted(box.face_attributes(random_fkey).keys()) == ['attr1', 'attr2']
+
+    box.face_attribute(random_fkey, "attr3", "value3")
+    assert sorted(box.face_attributes(random_fkey).keys()) == ['attr1', 'attr2', 'attr3']
+
+    assert box.face_attribute(random_fkey, "attr3") == 'value3'