diff --git a/docs/content/reference/static-configuration/env.md b/docs/content/reference/static-configuration/env.md
index e894850b2..d1758fa18 100644
--- a/docs/content/reference/static-configuration/env.md
+++ b/docs/content/reference/static-configuration/env.md
@@ -5,4 +5,23 @@ description: "Reference the environment variables for static configuration in Tr
 
 # Static Configuration: Environment variables
 
+!!! warning "Environment Variable Casing"
+
+    Traefik normalizes the environment variable key-value pairs by lowercasing them.
+    This means that when you interpolate a string in an environment variable's name,
+    that string will be treated as lowercase, regardless of its original casing.
+
+    For example, assuming you have set environment variables as follows:
+
+    ```bash
+        export TRAEFIK_ENTRYPOINTS_WEB=true
+        export TRAEFIK_ENTRYPOINTS_WEB_ADDRESS=:80
+
+        export TRAEFIK_CERTIFICATESRESOLVERS_myResolver=true
+        export TRAEFIK_CERTIFICATESRESOLVERS_myResolver_ACME_CASERVER=....
+    ```
+    
+    Although the Entrypoint is named `WEB` and the Certificate Resolver is named `myResolver`, 
+    they have to be referenced respectively as `web`, and `myresolver` in the configuration.
+
 --8<-- "content/reference/static-configuration/env-ref.md"