diff --git a/gnu/packages/aux-files/guile-launcher.c b/gnu/packages/aux-files/guile-launcher.c
index c205477f649..44f7e1f432a 100644
--- a/gnu/packages/aux-files/guile-launcher.c
+++ b/gnu/packages/aux-files/guile-launcher.c
@@ -84,11 +84,17 @@ int
 main (int argc, char **argv)
 {
   /* Try to install the current locale; remain silent if it fails.  */
-  if (setlocale (LC_ALL, "") == NULL)
-    /* The 'guix pull'-provided 'guix' includes at least en_US.utf8 so use
-       that.  That gives us UTF-8 support for 'scm_to_locale_string', etc.,
-       which is always preferable over the C locale.  */
-    setlocale (LC_ALL, "en_US.utf8");
+  char *locale = setlocale (LC_ALL, "");
+  if (locale == NULL || strcmp (locale, "C") == 0)
+    {
+      /* The 'guix pull'-provided 'guix' includes at least C.UTF-8 (which is
+	 baked into glibc, except when cross-compiling) so use that, and fall
+	 back to en_US.UTF-8.  That gives us UTF-8 support for
+	 'scm_to_locale_string', etc., which is always preferable over the C
+	 locale.  */
+      if (setlocale (LC_ALL, "C.UTF-8") == NULL)
+	setlocale (LC_ALL, "en_US.utf8");
+    }
 
   const char *str;
   str = getenv ("GUILE_LOAD_PATH");
diff --git a/guix/ui.scm b/guix/ui.scm
index eba12c86163..14d6874795a 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -521,7 +521,9 @@ part."
   "Install the current locale settings."
   (catch 'system-error
     (lambda _
-      (setlocale LC_ALL ""))
+      (when (string=? (setlocale LC_ALL "") "C")
+        ;; If the current locale is "C", prefer "C.UTF-8".
+        (setlocale LC_ALL "C.UTF-8")))
     (lambda args
       (display-hint (G_ "Consider installing the @code{glibc-locales} package
 and defining @code{GUIX_LOCPATH}, along these lines: