diff --git a/cli.py b/cli.py
index 240551a..dc96273 100755
--- a/cli.py
+++ b/cli.py
@@ -10,7 +10,7 @@
 
 
 def get_materials() -> dict:
-    with open("course.yml", "r") as f:
+    with open("course.yml", "r", encoding="utf8") as f:
         course = yaml.safe_load(f)
         materials = {
             lesson["slug"]: lesson.get("materials", []) for lesson in course["plan"]