diff --git a/python/src/pynumbuf/adapters/python.cc b/python/src/pynumbuf/adapters/python.cc
index 87cfef8d7..fd425a861 100644
--- a/python/src/pynumbuf/adapters/python.cc
+++ b/python/src/pynumbuf/adapters/python.cc
@@ -8,9 +8,13 @@ using namespace arrow;
 
 int32_t MAX_RECURSION_DEPTH = 100;
 
+extern "C" {
+
 extern PyObject* numbuf_serialize_callback;
 extern PyObject* numbuf_deserialize_callback;
 
+}
+
 namespace numbuf {
 
 Status get_value(ArrayPtr arr, int32_t index, int32_t type, PyObject* base, PyObject** result) {