diff --git a/Makefile b/Makefile
index ef56aec..940a80f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,12 @@
+ifeq ($(shell uname), Darwin)
+	PY_EXT := dylib
+else
+	PY_EXT := so
+endif
+
 test-python:
 	cargo build --release
-	cp target/release/libinstant_distance.dylib instant-distance-py/test/instant_distance.so
+	cp target/release/libinstant_distance.$(PY_EXT) instant-distance-py/test/instant_distance.so
 	PYTHONPATH=instant-distance-py/test/ python3 -m test
 
 clean: