Adolescent mental health remains a critical yet under-prioritized issue in low- and middle-income countries (LMICs) like Kenya, where resource limitations, stigma, and systemic barriers hinder access to care. While policies and strategies such as Kenya’s Mental Health Action Plan (2021–2025) exist on paper, their implementation is constrained by limited resources and a weak mental health service delivery infrastructure. This qualitative descriptive study examines the perspectives of mental health actors and youth advocates on the development and implementation of adolescent mental health policy in Kenya. Using a political economy analysis, we conducted 15 key informant interviews (KIIs) and analyzed observational field notes from a Google Jam board exercise to explore factors that enable or impede the prioritization of adolescent mental health policy and care. Thematic analysis was guided by Shiffman and Smith’s policy framework, focusing on four domains: actor power, ideas, political context, and issue characteristics. Findings reveal significant barriers, including the exclusion of adolescents from decision-making, limited family involvement, weak policy formulation, and the destabilizing effects of government transitions. Stigma, poverty, and chronic underfunding further hinder progress, despite ongoing strategic efforts. Comparisons with other LMICs indicate that these challenges are widespread, underscoring the need for localized, inclusive, and well-coordinated approaches. Addressing these issues will require strong political commitment, increased youth-led advocacy, and sustained investment in mental health services. By prioritizing adolescent mental health, Kenya can move toward a more equitable and effective mental health system that supports the wellbeing of its youth.