The main aim of this study is to gain insight into the characteristics and adverse consequences of using the TikTok application among elementary school students. Specific aims are to determine the characteristics of TikTok application use and the prevalence of harmful psychosocial consequences of excessive TikTok application use, as well as possible differences in the characteristics of TikTok use (frequency and adverse consequences) with regard to some sociodemographic and personal characteristics of the participants (gender, age/class, self-esteem). The study was conducted in March 2022 on a sample of 129 elementary school students from Martijanec Elementary School in Varaždin County and Vladimir Deščak Elementary School in Zagreb County. In this study, the Rosenberg Self-Esteem Scale - RSES (Rosenberg, 1965), the Internet Addiction Test - IAT (Young, 1996), and the Social Networking Usage Questionnaire - SNUQ (Gupta and Bashir, 2018) were used. In addition, questions were designed to gain insight into additional characteristics of TikTok application use (creation of own content, motivation for use, perception of risk of TikTok challenges, impact of the COVID -19 pandemic on frequency of use). The research results show that 81.5% of the participants opened a profile on TikTok, and more than half of them accessed the application for the first time when they were 10-11 years old. The highest percentage of pupils spend between 30 minutes and 2 hours (56%) on the application on weekdays, and between 30 minutes and 3 hours (71.9%) on weekends. Their own content on the app was created by 71.3% of participants, while 37% of them said they tried at least one TikTok challenge. As many as 85.2% of students believe that they learned something useful thanks to the application, and most of them use the application for fun (78.7%). More than half of the participants have no signs of addiction to the application, while 10.3% of the participants developed a moderate level, and none of them developed a high level of addiction. No statistically significant difference was found in the frequency of use of the application with regard to the gender. As for the difference in frequency of use in relation to grade, it was only found for use during the work week, in such a way that eighth-grade students used the application more frequently. In this study, no statistically significant differences were found in the presentation of adverse psychosocial consequences of excessive use of TikTok with regard to gender, class, and self-esteem of the participants. The results are discussed in the context of their implications for future scientific research and practical application, as well as potential limitations that should be considered.