Participatory action research and evaluation methods (PAR) have been used to help individuals to address a variety of challenges and improve the responsiveness of service systems to these challenges. To the present, however, few studies have examined applications of PAR in systems change advocacy for youth with mental health needs in the transition to adulthood (transition-age youth [TAY]). PAR may be especially beneficial in systems transformation efforts for this population, which lacks resources of other mental health system consumers for advocacy such as formal settings, specialized professional attention, and well established consumer organizations. The present paper describes how specific strategies for PAR, including Appreciative Inquiry and Photovoice, were employed in the Youth Appreciative Inquiry and Photovoice (YAP) project to: 1) gather perspectives of TAY in two statewide youth and family operated programs on needs and aspirations, current responsiveness of their programs and systems, and possible targets for program and system improvement; and 2) share these perspectives with stakeholders to effect change through a video. Findings on these perspectives as well as the impact of video showings are presented, and implications for systems change benefitting TAY and other populations facing systems-level challenges are discussed.