Parasocial Relationships, coined by Horton and Wohl (1956), are a type of one-sided relationship that is experienced between an audience and the performer. Though they cannot be reciprocated, people who have developed these relationships view them as other ordinary friendships (Eyal & Cohen, 2006). Historically these relationships were developed through television, however, with the advent of the internet, a new medium for interaction has been on the rise: Social Media. Social media has created a new avenue for these performer/viewer interactions by providing access to these celebrities and their content virtually anywhere and anytime. While there have been several instruments created to measure parasocial relationships in the past, and in a number of different contexts, none of them lend themselves to being implemented on celebrities of this new medium. The Parasocial Relationships in Social Media (PRISM) Survey was developed in order to address this gap in the literature. This multipart dissertation contains three papers investigating parasocial relationships and the methods used to measure them. The first paper explores the current instruments found in the communications, psychology, sociology, and marketing literature that have been designed to measure parasocial relationships, including their strengths, weaknesses, and areas for improvement. The second and third papers introduce the PRISM survey, how it was developed, and the methods used to validate it. The findings from studies two and three demonstrates the PRISM survey possess strong construct validity, reliability, and psychometric properties. Exploratory factor analyses conducted in paper two found the survey measures four dimensions of parasocial relations: Interest in, Knowledge of, Identification with, and Interaction with a given celebrity, while paper three found the survey to be invariant across different social media platforms. Together these papers support the PRISM survey’s ability to measure parasocial interactions created with online social media celebrities accurately across different social media platforms.