diff --git a/GitBook.gitignore b/GitBook.gitignore
index 333873a45fc6c66411ddf9952a4fe0456dc1140c..7cb665f280229802b60cfe7bd17bd462a0347f30 100644
--- a/GitBook.gitignore
+++ b/GitBook.gitignore
@@ -29,3 +29,8 @@ node_modules
 
 # Book build output
 _book
+
+# eBook build output
+*.epub
+*.mobi
+*.pdf