diff --git a/python-package/README.rst b/python-package/README.rst
index cee08c39f..96ad6a555 100644
--- a/python-package/README.rst
+++ b/python-package/README.rst
@@ -26,6 +26,11 @@ Please install ``gcc@5`` from `Homebrew <https://brew.sh/>`_::
 
     brew install gcc@5
 
+After installing ``gcc@5``, set it as your compiler::
+
+    export CC = gcc-5
+    export CXX = g++-5
+
 Linux
 -----