This study was conducted to determine the change in the sociability levels of high school students depending on the frequency of their using social media and to investigate their social media uses. It employed a mixed-methods research design using both quantitative and qualitative methods together. The sociability levels of 352 students studying in Siirt in 2018 were determined through the "Extraversion" sub-dimension of the Big Five Inventory for this purpose. Accordingly, it was found out that the sociability points of the students differed significantly depending on the frequency of their Youtube, Instagram, and WhatsApp use, but not depending on the frequency of their Facebook use. In addition, the social media uses of the students were investigated with semi-structured interviews made with 27 students who were social and often used social media. In accordance with this aim, the participants were found to use Youtube for entertaining and learning, Instagram for communicating and entertaining, and WhatsApp for communicating. It was concluded in the interviews that the social media uses of the students who often used social media reflect their sociability traits.