The use of social media has steadily grown in recent years, and now more than ever, people are logging on to websites like Facebook, Twitter, Foursquare, and Google Latitude with the aim of broadcasting their location information. The ability to 'check in' has enabled social network site users to broadcast detailed information about their whereabouts and also what they are doing there. This is encouraged by the implementation of location-based services (LBS) -technology which uses information about the geographical position of a mobile device. To date, little academic research has focused on perceptions of, or intentions to use these systems. This paper describes a study which utilised a psychological framework originally designed to predict intentions to use LBS, which was modified to assess intentions to use LBS within a social networking site (SNS) context. Participants completed an online survey, assessing their beliefs surrounding, and intentions to use, LBS via SNS. We find that trust of the social network provider as well as disclosure preferences influence intentions to use SNS with friends, family, and colleagues. This work highlights an important area of psychological research that has not previously been considered, and provides a theoretical foundation from which further work could explore location-tracking aspects of SNS.