This study explored secondary school students’ personal use of social media and psychological drivers that may underpin engagement. Six hundred ninety-five students, 5th to 8th grade, attending ten different public schools in Turkey completed an online questionnaire investigating social media engagement (SME), Fear of Missing Out (FoMO), and Problematic Internet Use (PIU). The study used a self-reported instrument as a measurement tool to investigate the extents of the research phenomena, consisting of three major sections: demographics questions, FoMO Scale, and Problematic Internet Use (PIU) Scale. The study was designed with the Correlational Research model. To examine the relationships between the groups, a Structural Equation Modeling Path Analysis was run. Our study observed a significant, positive, and moderate relationship between secondary school students’ levels of fear of missing out and levels of problematic internet use. There was also a significant, positive, and weak relationship between sharing frequency on social media engagement. Students’ levels of FoMO significantly and positively affected their levels of PIU. Students’ frequency of sharing on social media in a day significantly and positively affected their levels of FoMO. The time students spent on social media in a day significantly and negatively affected their levels of PIU. Future research may also examine the differences between the various social media sites and what protective characteristics, such as personality traits, can mitigate the influence of FoMO on PIU and social media engagement.