This study focused on exploring Internet abuse among teenagers and its relations to some Internet usage patterns and demographic characteristics in a digitalizing country, Turkey. It was designed as a cross-sectional research on three types of school that differ in their academic performances. The data were collected from 1380 high school students through a paper-based questionnaire. The results identified a small portion of students as Internet abusers experiencing severe problems and one fourth as possible abusers experiencing occasional problems in their lives. Excessive use, tolerance, preoccupation with the Internet, and using the Internet to escape from negative feelings were the most frequently reported symptoms of disturbed patterns of online behaviors. One-way between-groups ANOVA tests revealed that Internet abuse differed significantly based on gender and perceived academic achievement with small effect sizes, and frequency of Internet use, dominant place of Internet use and dominant purpose for Internet use with medium and large effect sizes. On the contrary, no significant differences were found based on perceived socio-economic status and the type of school attended. (Contains 6 tables.)