diff --git a/compose/env-file.md b/compose/env-file.md
index f543f32bcaa5..63920dd29bb4 100644
--- a/compose/env-file.md
+++ b/compose/env-file.md
@@ -13,6 +13,7 @@ named `.env` placed in the folder where the `docker-compose` command is executed
 These syntax rules apply to the `.env` file:
 
 * Compose expects each line in an `env` file to be in `VAR=VAL` format.
+* Lines not conforming to the above syntax **will be ignored**.
 * Lines beginning with `#` are processed as comments and ignored.
 * Blank lines are ignored.
 * There is no special handling of quotation marks. This means that