This chapter provides an introductory overview of the rationale for our co-designed action research project, which explores the scope of mental health peer support among young women. We begin by demonstrating the strong correlation between gender inequality, including experiences of gendered violence, and the mental health struggles faced by young women in Australia and other countries. We introduce the mixed-methods and participatory, action-oriented research design we employed, and make an argument for the benefits of using a co-design approach with young women. The language and tone used throughout the chapter purposefully seeks to demystify co-design research methods, especially for post-graduate and early-career researchers in social work and other social science disciplines.