diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index b8979cac19..1fb3505307 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -477,6 +477,7 @@ (define (optional-mapping->fs mapping)
                             (group-entry (gid 65534) ;the overflow GID
                                          (name "overflow"))))
             (home-dir (password-entry-directory passwd))
+            (logname  (password-entry-name passwd))
             (environ  (filter (match-lambda
                                 ((variable . value)
                                  (find (cut regexp-exec <> variable)
@@ -528,6 +529,10 @@ (define (optional-mapping->fs mapping)
                       ;; The same variables as in Nix's 'build.cc'.
                       '("TMPDIR" "TEMPDIR" "TMP" "TEMP"))
 
+            ;; Some programs expect USER and/or LOGNAME to be set.
+            (setenv "LOGNAME" logname)
+            (setenv "USER" logname)
+
             ;; Create a dummy home directory.
             (mkdir-p home-dir)
             (setenv "HOME" home-dir)