diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
index e43ead05bace179043fcc58a20c592f4ccbfa5f6..08c79ae119a5b9d6af2dd4b89d23dcc34d8f6ecc 100644
--- a/python/CMakeLists.txt
+++ b/python/CMakeLists.txt
@@ -45,6 +45,7 @@ set(pyarb_source
 # use by both the Python wrapper target (pyarb) and for the
 # unit tests of the C++ components in the Python wrapper.
 add_library(pyarb_obj OBJECT ${pyarb_source})
+set_target_properties(pyarb_obj PROPERTIES CXX_VISIBILITY_PRESET hidden)
 target_link_libraries(pyarb_obj PRIVATE arbor arborio pybind11::module)
 
 # The Python library. MODULE will make a Python-exclusive model.