This paper proposes three hypotheses for why adolescent sexual and reproductive health and rights (ASRHR) is under-financed and develops three theories of change to identify activities and themes for GFF focus. These include activities to: (1) close key gaps in the evidence base around the cost of adolescent health interventions; (2) efforts to strengthen health systems and capacity needed to strategically purchase a rights-based package of SRH interventions; and (3) efforts to address bottlenecks to multi-sectoral actions to unlock additional financing that can contribute to improved ASRHR outcomes.