Excessive mobile phone use, especially among adolescents, brings too many debates about its effects. To this end, in this study, we try to investigate the relationship between adolescents' mobile phone use and their self-esteem levels with regard to their genders. For 919 high school students, we evaluated mobile phone use concerning their self-esteem levels by using the Problem Mobile Phone Use Scale and Rosenberg Self-Esteem Scale. The findings indicate that there is a significant relationship between problematic phone use and self-esteem levels, and that there is also a significant difference between problematic mobile phone use and gender.