Background and aims: The current research aimed to discover classification concerning problematic smartphone use in children. Furthermore, to investigate their longitudinal trajectories, as well as to discover the connection concerning problematic smartphone usage by individual, parental, and school factors. Methods: A total of 2,399 South Korean children who were in the 4th grade (female 1,206 (50.3%), age 10-13 years) at baseline. Latent class growth analysis was utilized to discover typologies in problematic smartphone use and their longitudinal trajectories. Multinomial logistic regression analysis was used to find various associations among problematic smartphone use and individual, parental, as well as school factors. Results: The results identified three distinct trajectories of problematic smartphone use: (1) a high-level group (7.7%), (2) a mid-increasing group (62.5%), and (3) a low-increasing group (29.8%). The increasing group showed the highest level of problematic smartphone use. Gender, self-esteem, social withdrawal, exercise, parental inconsistency, monthly income, and teacher support were significant predictors. Discussion and Conclusions: The findings suggest that there are distinct developmental trajectories concerning problematic smartphone usage of childhood. The results show that the early discovery of children in danger of problematic smartphone use and targeted interventions aimed at reducing parental inconsistency and social withdrawal, improving self-esteem, exercise, and teacher support may be effective strategies for preventing problematic smartphone usage during childhood.  Kulcsszavak: problematic smartphone use, trajectories, latent class growth analysis, childhood