Purpose: This study was done to identify cell phone addiction in high school students and variables predicting this addiction. Methods: The participants were 469 adolescents from four high schools. Data were collected through self-report questionnaires, and analyzed using the SPSS program. Results: Of the high school students, 88.4% reported being average users, 7.5%, heavy users, and 4.1%, cell phone addicted. Cell phone addiction was significantly correlated with immediate self-control, self-efficacy, depression, and peer support. Predictors of cell phone addiction were the following: receiving text message on weekends, immediate self-control, main use (text message), minute per call on weekdays, listening to music, gender (female), monthly call charges, depression, person called (friends), and self-efficacy. These factors explained 39% of variance in cell phone addiction. Conclusion: The above findings indicate that cell phone addiction in high school students was influenced by gender, cell phone use, and psychological factors. Therefore the approach to effective cell phone addiction management for high school students is to consider these variables when developing programs for these students.