This property sets the preferred orientation mode for users with mobile devices. For the different modes available, see Enum/ScreenOrientation.

When a Player joins the game, if they are using a mobile device, this property will determine the device’s starting orientation. PlayerGui/ScreenOrientation will be set to this value for Player|Players joining the game. For example, the following code would set the default to ‘Portrait’:

game:GetService("StarterGui").ScreenOrientation = Enum.ScreenOrientation.Portrait

By default, this property is set to ‘LandscapeSensor’, meaning the viewport will rotate so it is always right-side-up in landscape.

Changing this property will not change the Enum/ScreenOrientation for Player|Players already in the game. To change the orientation for an existing player use their PlayerGui/ScreenOrientation property.

You can also get the current screen orientation for a user’s device using PlayerGui/CurrentScreenOrientation. This is useful when using the ‘sensor’ Enum/ScreenOrientation settings.

For more information, please see this article on Articles/Device Orientation for Mobile Roblox Games|device orientation.