This brief discusses initial learning emerging from the Adaptive approaches to reducing teenage pregnancy in Sierra Leone action research project. The project is accompanying three international NGOs - Concern, International Rescue Committee (IRC), and Save the Children - as they trial adaptive approaches to addressing teenage pregnancy in Sierra Leone. Key messages: 1) Partners under this action research project are trialling alternative approaches to preventing teenage pregnancy, focusing on social norms change. These components of their programmes are being managed adaptively; 2) Institutional context, space for reflection, and flexible operations processes (sub-granting, budgeting, recruitment) have emerged as key factors in allowing partners to work more adaptively, even across different implementation modalities; 3) Partners’ initial activities have focused strongly on learning about the problem and context. However, additional time and resources need to be dedicated to capacity-building, bringing on board new staff and partners, and communication.