As mobile computing and smartphones become an integrated part of our lives, the time individuals spend on social networks has significantly increased. Moreover, a link has been established between the uncontrolled use of social networks to the development of undesirable habits and behaviors including addictions. One such behavior, namely, fear of missing out (FOMO) is of particular interest and concern especially because of the widespread use of smartphones and computers, and thereby extensive use of social networks by the younger generation. This study establishes the relationships between FOMO and various social networks in an attempt to identify the problematic use of social media in Turkey and discover variables relevant to FOMO. The main objective of the study is to examine the prevalence of FOMO in preservice teachers. A total number of 363 preservice teachers on various academic courses were employed for the purpose of this study. The design was a survey which utilized a standardized questionnaire on FOMO together with a demographic questionnaire to explore the impact of the usage of smartphones and social networks by preservice teachers. The data were analyzed using descriptive statistics, independent samples t-tests, and analysis of variance (ANOVA). The overall findings of the study showed that the spread of FOMO amongst preservice teachers is at intermediate level. Significant differences were also found between groups based on gender, age, and usage of social networks. Furthermore, data from males were indicative of higher FOMO levels than female preservice teaches and again, under 21s were found to have higher levels of FOMO compared to the other age groups. A significant relationship was reported between being online on social networks throughout the day and active use of social media over seven hours, and FOMO. Furthermore, preservice teachers using Twitter, Instagram, Swarm, or Snapchat have increased levels of FOMO. Implications are discussed within current models.