This research project aimed at examining the interconnections between identity-based intrapsychic forces¬ — specifically, cultural identity, Australian identity, religiosity, and personal/ego identity— and psychological and socio-cultural adaptation of Australian adolescent Muslims. The study extends previous research on minority adolescents which mainly investigated the role adolescents’ acculturation modes play in their adaptation. The study employed a mixed-method design involving quantitative and qualitative methodologies. The quantitative part of the study recruited a sample of 321 high school Muslim students (149 males and 172 females) aged between 14 and 18 years studying at Muslim schools in metropolitan Sydney, Australia, who filled in a survey measuring among other things their cultural identity, Australian identity, religiosity, personal/ego identity, and adaptation. The qualitative part of this research project conducted semi-structured interviews with a subset of 18 Australian adolescent Muslims from the same cohort of participant schools. The interviews examined participants’ cultural identity, Australian identity, religiosity, and the role each plays in their adaptation. A series of hierarchical regression analyses, controlling for socio-demographic factors, revealed that while adolescents’ preference for integration of their cultural and Australian identities was advantageous for a range of their psychological and socio-cultural adaptation measures, marginalisation was consistently the worst. Similarly, while personal/ego identity achievement was advantageous for a range of adaptation measures among the participants, diffusion was consistently the worst. Further hierarchical regression analyses, controlling for socio-demographic factors, showed that adolescent Muslims’ religiosity, and to a certain degree their personal/ego identity achievement, was better for a range of their adaptation measures compared to their preference for an integration acculturation style. This finding was generally supported by the qualitative analysis revealing that adolescent Muslims were in a better position to see a positive role of religiosity in their adaptation, compared to their cultural identity or being Australian.