The purpose of this dissertation is to explore the relationships between mobile social media use, personality and loneliness. Snapchat, Facebook, Instagram, Twitter and texting were studied. Undergraduate students (N = 352) were given a survey to assess how they use social media generally, loneliness and personality traits, as well as how they used social media in specific relationships in their life—with a strong, close tie, and with a more casual acquaintance. A state of “phoneliness” is proposed where an individual’s social media use contributes to feelings of loneliness, which then in turn affect social media use. Overall, this study finds evidence to suggest social media have some emotional benefit. The more platforms one uses, the less lonely he or she is likely to be. Each social media application had initial benefits wherein moderate use was associated with decreased loneliness. However, each platform also had a point of diminishing returns (ranging from 30 minutes/day to an hour/day) after which further use either had no effect or was associated with increased loneliness. Results are discussed in light of media multiplexity theory and social presence theory.