First we hypothesized that individuals who have had their basic needs for competence, autonomy, and relatedness satisfied on a day-to-day basis would be lower in fear of missing out. Second, we hypothesized that FoMO would be negatively associated with indicators of psychological well-being. That is, we expected that experiencing lower levels of general mood and lower overall life satisfaction would report higher levels of FoMO. Finally, we hypothesized that FoMO is robustly related to social media use. Specifically, we predicted that FoMO would mediate the relations (if any) linking individual variation in basic need satisfaction, general mood, and life satisfaction to behavioral engagement with social media.