Achievement of a positive identity and its transition to adulthood is the most important task of the adolescent era. This cross-sectional explanatory mixed-method study sought to better understand barriers to identity development in female adolescents in Iran by explaining their own experiences and using a Positive Youth Development model as a framework. A total of 573 female secondary-school students were recruited through multistage sampling and were asked to complete the questionnaire of Developmental Assets Profile (DAP). Positive identity in DAP consists of four assets (personal power, self-esteem, a positive view of the personal future, and sense of purpose). Quantitative data analysis showed that among above mentioned four assets, personal power and self-esteem gained lower scores. A qualitative study held six individual interviews and two focused-group discussions were conducted to explain the barriers to personal power and self-esteem. Results showed that considering personal power, there were two categories as follows: (1) barriers to a sense of control over life and future (subcategories: being limited by failures, deprivation of liberty, and dissatisfaction from being excessively controlled by parents). (2) Barriers to adequately dealing with the challenges and problems (subcategories: expressing feelings inappropriately, isolation, and blaming). Barriers to self-esteem included categories of negative emotions due to weak academic performance, weak religious performance, weak communication with parents, and previous mistakes. The results of the present study highlighted the areas that need intervention in the field of promoting positive identity in adolescent girls and their parents.