High school students often face challenges and pressures, and two significant factors shaping their daily lives are stress and social media. Academic pressure, social dynamics, and societal expectations can be sources of stress among high school students. At the same time, social media is becoming an ubiquitous part of their lives, providing a platform for interaction, expression, and connection with peers. However, social media usage also comes with challenges, including the pressure to maintain "perfect" virtual identities and potential impacts on mental health. This research aimed to examine self-assessment of social media use on the perceived level of stress among high school students. Differences in perception were investigated based on gender, grade level, type of high school, average daily social media usage, and the most common activities on social media. The study involved 77 high school students from the city of Split. The research results can contribute to a better understanding of the stressful situations that today's high school students face, as well as their overall mental health. Additionally, they can assist creators of preventive programs related to social media usage in highlighting both the shortcomings and advantages of such usage. For scientists, this research can serve as a stimulus for further exploration in this highly relevant research area.