diff --git a/website/docs/configuration/variables.html.md b/website/docs/configuration/variables.html.md
index d29bdb6a9f..6d130a6a60 100644
--- a/website/docs/configuration/variables.html.md
+++ b/website/docs/configuration/variables.html.md
@@ -339,3 +339,6 @@ has the last definition loaded.
 
 Definition files passed using the `-var-file` flag will always be evaluated after
 those in the working directory.
+
+Values passed within definition files or with `-var` will take precedence over
+`TF_VAR_` environment variables, as environment variables are considered defaults.