Introduction: Social networks lead to social comparisons, self-evaluation and creation of selfimage, which can affect users positively or negatively. A particularly vulnerable group of social network users are adolescents. Adolescence is considered an emotionally intense and stressful period in which independence is established, a strong identity is created and the focus is placed on oneself. Objective: The main objective of this research is to examine the importance of social networks on creating a self-image, the frequency of negative experiences on social networks and the level of self-esteem of Karlovac medical school students in the context of social networks. Methods: A total of 126 students of the high school of medicine in Karlovac participated in the research. The influence of social networks on the creation of self-image and the frequency of negative experiences on the Internet was examined with author's questionnaires, and self-esteem was examined with the Rosenberg self-esteem scale. Results: Age was not a significant factor for self-image and exposure to violence on social networks. Female students achieved a statistically significantly lower level of self-esteem than male students. The number of friends/followers and the time spent on social networks did not have a statistically significant effect on the level of self-esteem. The level of self-esteem increases with the increase in the number of close friends. The number of friends/followers and time spent on social networks were not significant predictors of the perceived importance of social networks on self-image formation. Conclusion: Although our research did not show a significant influence of social networks on the self-esteem of the observed sample of students, social networks have both positive and negative aspects of influence on self-esteem. The use of social networks can be very useful for social connection, a sense of belonging and acceptance, but it can also have psychologically negative effects such as Internet addiction and a focus on one's own appearance that results in self-objectification.