diff --git a/alpine/Dockerfile b/alpine/Dockerfile
index 15236ae3548f5d9e7c114a71fe9b4930d518cad8..f6f83e27d79036bb95b09877727bec1c1107f64f 100644
--- a/alpine/Dockerfile
+++ b/alpine/Dockerfile
@@ -21,7 +21,7 @@ RUN apk add --no-cache --virtual .download \
     rm dockerize-alpine-linux-amd64-$DOCKERIZE_VERSION.tar.gz && \
     apk del .download
 
-ENV GOSU_VERSION 1.11
+ENV GOSU_VERSION=1.11
 COPY [ "resources/gosu-gpg.key", "/tmp/gosu.key" ]
 RUN set -ex; \
     \