The aim of the present study was to detect both sociodemographic factors related to possible Internet addiction and the prevalence of this addiction, as well as to determine the relationship between possible Internet addiction and self-injurious behavior, life satisfaction, and the level of loneliness in adolescents attending high school in the city center of Isparta. A cross-sectional analytic study was planned for high school adolescents. An information form concerning Internet usage and related sociodemographic factors, Internet Addiction Scale, Satisfaction with Life Scale, and a UCLA Loneliness Scale-Short Form were applied to the students. The prevalence of possible Internet addiction was found to be 14.4%. Adolescents with possible Internet addiction were found to have low levels of loneliness and high levels of life satisfaction. The results are then discussed in light of the related literature.