diff --git a/engine/admin/systemd.md b/engine/admin/systemd.md
index a4b7d0160b..53239c0392 100644
--- a/engine/admin/systemd.md
+++ b/engine/admin/systemd.md
@@ -62,6 +62,8 @@ To accomplish this, set the following flags in the `daemon.json` file:
 
 ### HTTP proxy
 
+>**Note:** The same instructions work for `HTTS_PROXY` as well.
+
 The Docker daemon uses the `HTTP_PROXY` and `NO_PROXY` environmental variables in
 its start-up environment to configure HTTP proxy behavior. You cannot configure
 these environment variables using the `daemon.json` file.