The aim of this research is to examine the predictive role of authenticity in internet addiction. The research was carried out with 420 high school students (280 females and 140 males). The data were obtained by using the Internet Addiction Scale and the Authenticity Scale. Correlation and multiple regression analysis were performed in which the dependent variable was internet addiction and the independent variables were subscales of authenticity. Correlation analysis showed that internet addiction was correlated negatively with authentic living and positively with self-alienation and accepting external influence. According to the results of the multiple regression analysis, self-alienation entered the equation first, accounting for 21% of the variance in predicting internet addiction. Authentic living entered on the second step accounting for an additional 7% variance. Accepting external influence entered on the third step accounting for an additional 3% variance. The standardized beta coefficients indicated the relative influence of the variables in last model with self-alienation, authentic living, and accepting external influence, all significantly influencing internet addiction and self-alienation was the strongest predictor.