diff --git a/_toc.yml b/_toc.yml
index b3b94d9b..59d79923 100644
--- a/_toc.yml
+++ b/_toc.yml
@@ -23,6 +23,7 @@ chapters:
       - file: user-guide/xrdp
       - file: user-guide/ssh_host_key_certificates
       - file: user-guide/ssh_client_config
+      - file: user-guide/env_variables
       - file: user-guide/firefox_profile_per_host
       - file: user-guide/kerberos_lifetime
       - file: user-guide/mpirun