It is not well understood why some detained female adolescents refrain from offending whereas others do not. The majority of prospective studies with these females adopt a risk management (instead of a strength-based empowering) perspective, thereby risking to overlook crucial keys to support females’ rehabilitation. The present study takes an important next step towards a strength-based empowering perspective on detained female adolescents by studying their quality of life (QoL) to explain offending outcomes in emerging adulthood, relying on the strength-based Good Lives Model (GLM) of offender rehabilitation. The study consists of a mixed method, long-term prospective design in a sample of 147 detained female adolescents: it includes a quantitative and qualitative follow-up measurement 4 years after detention (T4), building on prior measurements at the start (T0), during (T1-2) and 6 months after detention (T3). We aim to produce statistics about as well as in-depth insight into females’ own perspective on (i) developmental experiences impacting their QoL and offending behavior; (ii) capacities/obstacles and adopted (in)appropriate means in achieving their QoL; and (iii) (in)direct pathways from QoL to offending in emerging adulthood. This project will improve understanding of females’ QoL in relation to future offending behavior, and bears the promise to develop new, empowering insights that could improve rehabilitation theories.