diff --git a/gnu/services/guix.scm b/gnu/services/guix.scm
index 2b1b69589e..a47c4bd941 100644
--- a/gnu/services/guix.scm
+++ b/gnu/services/guix.scm
@@ -535,7 +535,7 @@ (define (guix-data-service-shepherd-services config)
                 #:environment-variables
                 `(,(string-append
                     "GUIX_LOCPATH=" #$glibc-utf8-locales "/lib/locale")
-                  "LC_ALL=en_US.utf8")
+                  "LC_ALL=en_US.UTF-8")
                 #:log-file "/var/log/guix-data-service/web.log"))
       (stop #~(make-kill-destructor)))
 
@@ -559,7 +559,7 @@ (define (guix-data-service-shepherd-services config)
                   "GIT_SSL_CAINFO=/etc/ssl/certs/ca-certificates.crt"
                   ,(string-append
                     "GUIX_LOCPATH=" #$glibc-utf8-locales "/lib/locale")
-                  "LC_ALL=en_US.utf8")
+                  "LC_ALL=en_US.UTF-8")
                 #:log-file "/var/log/guix-data-service/process-jobs.log"))
       (stop #~(make-kill-destructor))))))