There is growing recognition of the need to integrate community voice, vision and decision making into the design and delivery of development programs. The Holistic, Community-Led Development (HCLD) approach has demonstrated this integration can work in practice, yet there is limited understanding of this approach and of its effectiveness. The Full Spectrum Evidence and Learning Initiative (FSELI) is a collaboration of NGOs, grassroots practitioners, and researchers committed to enabling a systemic shift in how HCLD is understood and implemented. At its core are two organizations—Tostan and One Village Partners—that have witnessed participatory social transformation firsthand over decades. Alongside them are researchers from Institute of Development Studies with support from IDInsight. This initiative, catalyzed by Legado and having completed initial theoretical and methodological work, is now moving to a multi-year, multi-country, mixed-methods evaluation that will identify how and why HCLD works.