diff --git a/ensure_sorted.py b/ensure_sorted.py
index 700c3211..50b6683c 100755
--- a/ensure_sorted.py
+++ b/ensure_sorted.py
@@ -54,10 +54,10 @@ def __repr__(self):
         return self.__str__()
 
 def main():
-    readme_file = open('README.md', 'r')
     # start of the Apps section
     APPS_LINE_START = '## – Apps –\n'
-    lines = readme_file.readlines()
+    with open('README.md', 'r') as readme_file:
+        lines = readme_file.readlines()
 
     index: int
     try: