GIS applications have gone through the same trends in licensing as the broader software industry. This article focuses on GIS software, but will also address data as it is inextricably linked to GIS software and GIS more broadly. We begin with some key legal concepts applying to intellectual property in general and software specifically. This is followed by sections on historical and current GIS licensing. We then discuss licensing of GIS data. We close with practical considerations for GIS users and developers.