Objectives: Hong Kong has among the highest mobile phone usage rates in Asia. Although the mobile phone may foster adolescents' communication with parents and peers, there is also concern that some teens may become dependent on the mobile phone. The present study investigated the psychometric properties of the Mobile Phone Dependence Questionnaire (MPDQ) in a sample of young adolescents. Method: The MPDQ was translated and validated in a Hong Kong sample of adolescents (N = 733) from S1 (ages 11-12), S2 (ages 12-13), and S5 (ages 16-17) in six schools representing various levels of socioeconomic status. A subset of 27 students participated in focus groups on the topic of adolescents' mobile phone usage. Result: Confirmatory factor analysis identified three psychological factors represented in adolescents' responses to the MPDQ: compulsive text messaging, making and receiving a high number of calls, and obsessive thinking about using the mobile phone. Using the criterion of a score 2 standard deviations above the mean, 3.41% of students would be classified as showing mobile phone dependency, with a higher rate among females than males. Discussion: Positive examples of mobile phone usage were mobile parenting to monitor children, and children's use of the phone to seek mobile tutoring from teachers. E-counselling and e-tutoring are suggested as ways to provide support to adolescents using technology that is already an integral part of their lives.