diff --git a/conkeror/.conkerorrc/init.js b/conkeror/.conkerorrc/init.js
index 2f1b61b..081042e 100644
--- a/conkeror/.conkerorrc/init.js
+++ b/conkeror/.conkerorrc/init.js
@@ -193,6 +193,10 @@ theme_load("yoshi");
 
 external_content_handlers.set("application/pdf", "zathura");
 external_content_handlers.set("application/vnd.ms-excel", "libreoffice");
+external_content_handlers.set(
+    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+    "libreoffice"
+);
 
 var gh_url = "http://github.com/";
 function read_url_github_repo_command_handler(input)