This study provides an account of the phenomenon of internet addiction from the perspective of academic achievement. In other words, this study aimed to explore the relation between academic performance of Turkish high school students in such different subject as Maths, English, History, GPA and their use of internet. Different school subjects were selected consciously as the predictor of success in different domains such as social sciences, language, mathematics and the mean of them (GPA). In this respect, employing convenience sampling method, 217 high school students (107 males, 110 females) were included in the study. The level of internet addiction among the participants was determined through administering one dimension of the adopted version of The Social Networking and Social Media Status Scale (Arslan & Kirik, 2013) (a = 0.88). For academic performance, the students were asked to write down the grade points for the specified three subjects and GPA as in their recent school reports. Following the statistics and the procedures run for the reliability and validity of the scale using both SPSS 21 and Liesrel 6 for Windows; adequacy of the sampling; normality and homogeneity of the distribution, parametric tests (Independent Sample T tests & Pearson Product Moment Correlation) were run to analyze the data through SPSS 21 for Windows. The results suggested no gender impact on internet addiction. In terms of the academic performance, statistically positive relation was found between EFL performance and internet use while GPA scores were found to be negatively correlated with it. No correlation between performance in history or math and internet use was found.