This document describes the Care Group Trio model used in Bangladesh to promote behavior change around maternal and child health. The model involves forming groups of mothers, fathers, and grandmothers as leaders to influence their peers. Research showed these individuals most strongly influence health behaviors. Groups meet separately with a promoter then jointly to discuss challenges and solutions. An evaluation found increased rates of behaviors like exclusive breastfeeding and antenatal care. Lessons include practicing counseling skills, recognizing high performers, and meeting barrier identification with problem-solving and accountability across the trios.