diff --git a/README.md b/README.md
index 2c619302..1adddbfa 100644
--- a/README.md
+++ b/README.md
@@ -249,7 +249,7 @@ builder:
 
 This build secret can then be referenced in the Dockerfile:
 
-```
+```dockerfile
 # Copy Gemfiles
 COPY Gemfile Gemfile.lock ./