diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 6e6346a3..f1a3dc13 100755
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -3372,6 +3372,7 @@ Python:
   color: "#3572A5"
   extensions:
   - ".py"
+  - ".py3"
   - ".bzl"
   - ".cgi"
   - ".fcgi"
diff --git a/samples/Python/py3.py3 b/samples/Python/py3.py3
new file mode 100644
index 00000000..f7cf60e1
--- /dev/null
+++ b/samples/Python/py3.py3
@@ -0,0 +1 @@
+print("Hello, world!")