Peer-led and youth-led sex education primarily involves young people teaching other young people about sex, sexuality, and sexual health. This approach gained in popularity during the HIV/AIDS crisis of the 1980s–1990s, as community organizations sought to address the unique sexual health needs of lesbian, gay, bisexual, transgender, and queer (LGBTQ) youth, many of whom had been underserved in traditional sex education spaces. Since then, peer-led and youth-led sex education pedagogies have been implemented by researchers, educators, and community organizations working across a range of sites around the globe. Peer-led and youth-led sex education generally draws on assumptions that young people are better situated than adults to talk to their peers about sexual health and/or to model positive sexual health behavior. However, some have noted that this perspective constructs young people as a homogenous group and ignores the ways in which sexuality and sexual health intersects with other social factors. Furthermore, there is a general lack of consensus across interventions around who constitutes a “peer” and what constitutes “peer-led” sex education, resulting in the development of interventions that at times tokenize young people, without engaging them in meaningful ways. As a result, evaluations of many peer- and youth-led sex education pedagogies suggest that even as these pedagogies improve young people’s knowledge of sexual health-related topics, they often don’t result in long-term sexual health behavior change. However, many evaluations of peer- and youth-led sex education pedagogies do suggest that acting as a peer educator is of immense benefit to those who take on this role, pointing to the need for program developers to reconsider what effective sex education pedagogy might look like. A “social ecology” or “systems thinking” approach to youth sexual health may provide alternative models for thinking about the future of peer-led and youth-led sex education. These approaches don’t task peer- and youth-led sex education with the sole responsibility of changing young people’s sexual health-related outcomes, but rather situate peer-led sex education as one potential node in the larger confluence of factors that shape and constrain young people’s sexual health.