diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0c80e89293e06249c1c48d39bd7966514e41a299..241ce112ac74bc59c2a905d8f1ecb9dba5da6ef8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -715,6 +715,8 @@ release-x86_64-linux-centos7:
     BIN_DIST_PREP_TAR_COMP: "ghc-x86_64-centos7-linux.tar.xz"
     # pxz is not available on centos7 for reasons I can't understand
     XZ: "xz"
+    # CentOS seems to default to ascii
+    LANG: "en_US.UTF-8"
   only:
     - tags
   cache: