A central tenet of forensic mental health assessment is the use of multiple sources of data. Traditionally, these sources have included clinical interviews with and observations of the examinee, written records review, psychological test data, and interviews with collateral sources. Data from social media and social networking sites (SNS) is now widely used in civil litigation. However, existing professional practice standards and guidelines do not specifically address the use of SNS data. This leaves forensic mental health evaluators with little guidance as to why, when and how to incorporate SNS data into their evaluations. We review the extant literature on the use of SNS and other social media data in personal injury and disability cases, including legal, ethical, and practical considerations, with the goal of providing forensic mental health practitioners with a framework for making decisions about when and how to incorporate these data into their evaluations and opinions. We advocate caution in conducting independent searches of social media and the Internet, and in making inferences about internal states based on SNS postings. To illustrate these points, we include a case study.