diff --git a/GitBook.gitignore b/GitBook.gitignore
index 333873a4..7cb665f2 100644
--- a/GitBook.gitignore
+++ b/GitBook.gitignore
@@ -29,3 +29,8 @@ node_modules
 
 # Book build output
 _book
+
+# eBook build output
+*.epub
+*.mobi
+*.pdf