The Gender, Violence, and Health Centre (GVHC) at the London School of Hygiene and Tropical Medicine (LSHTM) has launched a learning and reflection group on social norms and gender-based violence (GBV). There is increasing interest among donors and practitioners to harness insights from social norms theory to catalyse change around gender inequity and harmful gender-related practices. Little guidance is available, however, to help practitioners integrate simple norms measures and change strategies within field-based programming. As theory-based insights open promising avenues for achieving change, a gap emerged between theory and its application within development practice. The mission of this group is thus: To translate and adapt insights and methods from social norm theory and research into practical guidance for development practitioners seeking to transform harmful gender-related practices in low and middle-income countries. Participants share and discuss individual solutions to common dilemmas around measurement and practice. Together, we are working on a programme of research and practice to test strategies that can help people negotiate new positive norms, and/or dismantle norms that keep harmful practices in place. Our collective experience will inform the next wave of intervention evaluation and norms measurement. As part of the learning initiative, LSHTM convened an expert group meeting in July 2016 on the measurement of social norms sustaining GBV. The meeting focused on identifying best-practice strategies to diagnose and measure social norms. Participants were drawn from groups that already had data and research experience attempting to capture gender-related norms and practices in the field. The meeting was kept relatively small to ensure productive exchange among the few teams that have experimented with different strategies for collecting quantitative data on norms and gender-based violence.