diff --git a/docker/base/Dockerfile.j2 b/docker/base/Dockerfile.j2
index 16c0e1d5ab..cf803d0894 100644
--- a/docker/base/Dockerfile.j2
+++ b/docker/base/Dockerfile.j2
@@ -4,7 +4,7 @@ LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build
 {% block base_lang %}
 # NOTE(yoctozepto): use a UTF-8 (Unicode) locale like standard image installs do
 # fixes issues arising from ascii fallback usage
-ENV LANG C.UTF-8
+ENV LANG en_US.UTF-8
 {% endblock %}
 
 {# NOTE(SamYaple): Avoid uid/gid conflicts by creating each user/group up front. #}
diff --git a/releasenotes/notes/unicode-locale-018fe01eaccc556d.yaml b/releasenotes/notes/unicode-locale-018fe01eaccc556d.yaml
index b248f91bf9..0052cd31a5 100644
--- a/releasenotes/notes/unicode-locale-018fe01eaccc556d.yaml
+++ b/releasenotes/notes/unicode-locale-018fe01eaccc556d.yaml
@@ -1,7 +1,7 @@
 ---
 upgrade:
   - |
-    ``C.UTF-8`` is set as the default locale (``LANG``) for images.
+    ``en_US.UTF-8`` is set as the default locale (``LANG``) for images.
     This affects both build- and run-time.
     Distributions supported by Kolla default to UTF-8 locale in
     installs so this change should provide a more expected experience.