diff --git a/.gitignore b/.gitignore
index 1f32c4ee..131fb2f6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,8 @@ data/
 
 # IntelliJ files
 .idea/
+
+# Jupyter checkpoint directories, which Jupyter writes beside any notebook it
+# opens -- currently only documentation/, but the rule is left unanchored so it
+# also covers notebooks added elsewhere later.
+.ipynb_checkpoints/