The aim of this study is to examine the Internet addiction among adolescents in relation to their sociodemographic characteristics, communication skills, and perceived familial social support. This cross-sectional research is conducted in the high schools in some city centers, in Turkey, in 2013. In this study, cluster sampling was used. In each school, a class for each grade level was randomly selected, and all the students in the selected classes were included in the sample. One thousand seven hundred forty-two students aged between 14 and 20 years were included in the sample.The mean Internet Addiction Scale (IAS) score of the students was found to be 27.9 ± 21.2. According to the scores obtained from IAS, 81.8% of the students were found to display no symptoms (<50 points), 16.9% were found to display borderline symptoms (50-79 points), and 1.3% were found to be Internet addicts (≥80 points). According to the results of the binary logistic regression, male students and the students in single sex vocational schools were found to report higher levels of borderline Internet addiction. It was also observed that the IAS score increases when the father's educational level increases and when the students' school performance is worse. On the other hand, the IAS score decreases when the student grade level, perceived family social support, and communication skills scores increase.The risk factors for Internet addiction are being a male, low academic achievement, inadequate social support and communication skills, and father's high educational level.