diff --git a/lib/config.cc b/lib/config.cc
index ab45ae7b..38416632 100644
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -22,6 +22,8 @@
 #include "notmuch-private.h"
 #include "database-private.h"
 
+#include <pwd.h>
+
 static const std::string CONFIG_PREFIX = "C";
 
 struct _notmuch_config_list {
@@ -451,6 +453,41 @@ notmuch_config_get_bool (notmuch_database_t *notmuch, notmuch_config_key_t key,
     return NOTMUCH_STATUS_SUCCESS;
 }
 
+static const char *
+_get_name_from_passwd_file (void *ctx)
+{
+    long pw_buf_size;
+    char *pw_buf;
+    struct passwd passwd, *ignored;
+    const char *name;
+    int e;
+
+    pw_buf_size = sysconf (_SC_GETPW_R_SIZE_MAX);
+    if (pw_buf_size == -1) pw_buf_size = 64;
+    pw_buf = (char *) talloc_size (ctx, pw_buf_size);
+
+    while ((e = getpwuid_r (getuid (), &passwd, pw_buf,
+			    pw_buf_size, &ignored)) == ERANGE) {
+	pw_buf_size = pw_buf_size * 2;
+	pw_buf = (char *) talloc_zero_size (ctx, pw_buf_size);
+    }
+
+    if (e == 0) {
+	char *comma = strchr (passwd.pw_gecos, ',');
+	if (comma)
+	    name = talloc_strndup (ctx, passwd.pw_gecos,
+				   comma - passwd.pw_gecos);
+	else
+	    name = talloc_strdup (ctx, passwd.pw_gecos);
+    } else {
+	name = talloc_strdup (ctx, "");
+    }
+
+    talloc_free (pw_buf);
+
+    return name;
+}
+
 static const char *
 _notmuch_config_key_to_string (notmuch_config_key_t key)
 {
@@ -486,6 +523,7 @@ static const char *
 _notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 {
     char *path;
+    const char *name;
 
     switch (key) {
     case NOTMUCH_CONFIG_DATABASE_PATH:
@@ -505,10 +543,18 @@ _notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 	return "inbox;unread";
     case NOTMUCH_CONFIG_SYNC_MAILDIR_FLAGS:
 	return "true";
+    case NOTMUCH_CONFIG_USER_NAME:
+	name = getenv ("NAME");
+	if (name)
+	    name = talloc_strdup (notmuch, name);
+	else
+	    name = _get_name_from_passwd_file (notmuch);
+
+	return name;
+	break;
     case NOTMUCH_CONFIG_HOOK_DIR:
     case NOTMUCH_CONFIG_BACKUP_DIR:
     case NOTMUCH_CONFIG_NEW_IGNORE:
-    case NOTMUCH_CONFIG_USER_NAME:
     case NOTMUCH_CONFIG_PRIMARY_EMAIL:
     case NOTMUCH_CONFIG_OTHER_EMAIL:
 	return NULL;
diff --git a/test/T590-libconfig.sh b/test/T590-libconfig.sh
index 49cc382a..2c6e726c 100755
--- a/test/T590-libconfig.sh
+++ b/test/T590-libconfig.sh
@@ -384,6 +384,9 @@ cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR} '' %NULL%
     }
 }
 EOF
+
+notmuch_passwd_sanitize < OUTPUT > OUTPUT.clean
+
 cat <<'EOF' >EXPECTED
 == stdout ==
 MAIL_DIR
@@ -396,11 +399,11 @@ NULL
 true
 NULL
 NULL
-NULL
+USER_FULL_NAME
 == stderr ==
 EOF
 unset MAILDIR
-test_expect_equal_file EXPECTED OUTPUT
+test_expect_equal_file EXPECTED OUTPUT.clean
 
 backup_database
 test_begin_subtest "override config from \${NOTMUCH_CONFIG}"
@@ -727,6 +730,8 @@ cat c_head2 - c_tail <<'EOF' | test_C ${MAIL_DIR} /nonexistent %NULL%
     }
 }
 EOF
+
+notmuch_passwd_sanitize < OUTPUT > OUTPUT.clean
 cat <<'EOF' >EXPECTED
 == stdout ==
 MAIL_DIR
@@ -739,10 +744,10 @@ NULL
 true
 NULL
 NULL
-NULL
+USER_FULL_NAME
 == stderr ==
 EOF
-test_expect_equal_file EXPECTED OUTPUT
+test_expect_equal_file EXPECTED OUTPUT.clean
 
 backup_database
 test_begin_subtest "override config from \${HOME}/.notmuch-config (ndlc)"
diff --git a/test/test-lib.sh b/test/test-lib.sh
index fc176af8..fa2e401e 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -694,6 +694,13 @@ notmuch_built_with_sanitize ()
     sed 's/^built_with[.]\(.*\)=.*$/built_with.\1=something/'
 }
 
+notmuch_passwd_sanitize ()
+{
+    local user=$(id -un)
+    local full_name=$(getent passwd $user | cut -d: -f 5 | cut -d, -f1)
+    sed "s/$full_name/USER_FULL_NAME/"
+}
+
 notmuch_config_sanitize ()
 {
     notmuch_dir_sanitize | notmuch_built_with_sanitize