diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index 8bd7fa684..09d1071ea 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -47,7 +47,7 @@ sub OnInit {
     $self->{notifier} = Slic3r::GUI::Notifier->new;
     
     # locate or create data directory
-    $datadir = Wx::StandardPaths::Get->GetUserDataDir;
+    $datadir ||= Wx::StandardPaths::Get->GetUserDataDir;
     Slic3r::debugf "Data directory: %s\n", $datadir;
     my $run_wizard = (-d $datadir) ? 0 : 1;
     for ($datadir, "$datadir/print", "$datadir/filament", "$datadir/printer") {
diff --git a/slic3r.pl b/slic3r.pl
index 2e9c87072..cc0af0a60 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -27,6 +27,7 @@ my %cli_options = ();
         'save=s'                => \$opt{save},
         'load=s@'               => \$opt{load},
         'ignore-nonexistent-config' => \$opt{ignore_nonexistent_config},
+        'datadir=s'             => \$opt{datadir},
         'export-svg'            => \$opt{export_svg},
         'merge|m'               => \$opt{merge},
     );
@@ -71,6 +72,10 @@ if ($opt{save}) {
 my $gui;
 if (!@ARGV && !$opt{save} && eval "require Slic3r::GUI; 1") {
     $gui = Slic3r::GUI->new;
+    {
+        no warnings 'once';
+        $Slic3r::GUI::datadir = $opt{datadir} if $opt{datadir};
+    }
     $gui->{skeinpanel}->load_config_file($_) for @{$opt{load}};
     $gui->{skeinpanel}->load_config($cli_config);
     $gui->MainLoop;