diff --git a/gtsam/gtsam.i b/gtsam/gtsam.i
index 295d5237f..b962724b9 100644
--- a/gtsam/gtsam.i
+++ b/gtsam/gtsam.i
@@ -2168,6 +2168,7 @@ virtual class NoiseModelFactor: gtsam::NonlinearFactor {
 
 #include <gtsam/nonlinear/CustomFactor.h>
 virtual class CustomFactor: gtsam::NoiseModelFactor {
+  // Note CustomFactor will not be wrapped for MATLAB, as there is no supporting machinery there.
   CustomFactor();
   CustomFactor(const gtsam::SharedNoiseModel& noiseModel, const gtsam::KeyVector& keys, const gtsam::CustomErrorFunction& errorFunction);
 };
diff --git a/python/gtsam/specializations.h b/python/gtsam/specializations.h
index c7f45fc0f..c6efd2f71 100644
--- a/python/gtsam/specializations.h
+++ b/python/gtsam/specializations.h
@@ -2,9 +2,12 @@
 // These are required to save one copy operation on Python calls
 #ifdef GTSAM_ALLOCATOR_TBB
 py::bind_vector<std::vector<gtsam::Key, tbb::tbb_allocator<gtsam::Key> > >(m_, "KeyVector");
+py::implicitly_convertible<py::list, std::vector<gtsam::Key, tbb::tbb_allocator<gtsam::Key> > >();
 #else
 py::bind_vector<std::vector<gtsam::Key> >(m_, "KeyVector");
+py::implicitly_convertible<py::list, std::vector<gtsam::Key> >();
 #endif
+
 py::bind_vector<std::vector<gtsam::Point2, Eigen::aligned_allocator<gtsam::Point2> > >(m_, "Point2Vector");
 py::bind_vector<std::vector<gtsam::Point3Pair> >(m_, "Point3Pairs");
 py::bind_vector<std::vector<gtsam::Pose3Pair> >(m_, "Pose3Pairs");
diff --git a/python/gtsam/tests/test_custom_factor.py b/python/gtsam/tests/test_custom_factor.py
index e8f06b27a..32ae50590 100644
--- a/python/gtsam/tests/test_custom_factor.py
+++ b/python/gtsam/tests/test_custom_factor.py
@@ -36,7 +36,7 @@ class TestCustomFactor(GtsamTestCase):
             return error
         
         noise_model = gtsam.noiseModel.Unit.Create(3)
-        cf = CustomFactor(noise_model, gtsam.KeyVector([0]), error_func)
+        cf = CustomFactor(noise_model, [0], error_func)
         v = Values()
         v.insert(0, Pose2(1, 0, 0))
         e = cf.error(v)