Social Networking Sites (SNS) are the bread and butter of our digital lives, but research has shown SNS usage to lead to higher levels of Fear of Missing Out (FOMO) and lower levels of subjective wellbeing (Przybilski, Murayama, Dehaan, & Gladwell, 2013). Existing psychological theories explain this causal relationship as an outcome of either an innate need for relatedness (Self Determination Theory) or behavioral addiction (SNS Addiction). Theoretically, these theories also posit that individuals with a greater number of SNS (...) accounts are also more likely to experience FOMO and in turn lower levels of subjective wellbeing. The aim of this paper is to investigate this hypothesis, through a post hoc analysis of data previously obtained for a college project. Our sample consisted of 181 participants (Males = 57, Females = 123, Others = 1) with the mean age being 21.51 (SD = 1.76). Results show FOMO to completely indirectly mediate the relationship between number of SNS accounts used and subjective wellbeing (effect = -.20, SE = .10, CI = -.43 to -.03); supporting our hypothesis. Future directions for research and interventions are discussed. (shrink)