Despite considerable progress within wilderness and adventure therapy research over the last decade, researchers are still unable to precisely answer why, how, and for whom this treatment modality works. There is also a need for more knowledge regarding the circumstances under which the treatment does not appear to be effective. In this realist synthesis, we attempt to unpack this "black box" of wilderness therapy more specifically, defined as a specialized approach to mental health treatment for adolescents. Through a focused review of the primary qualitative wilderness therapy studies, empirical findings are used to test and refine a key program theory. The synthesis results in a proposed wilderness therapy clinical model and offers informed implications for future theory development, research, and practice.