In this Major Research Project (MRP), I highlight community-driven innovations in response to COVID-19, focusing on case studies from social innovation labs and organizations (referred to as “Labs”) in Ontario, Canada. These Labs, which address the social determinants of health both within and outside the formal healthcare system, played a key role in supporting, supplementing, and scaling grassroots emergency response efforts aimed at reducing health inequities during the pandemic. Drawing on interviews with 10 social innovation practitioners and designers, this MRP argues that the role and value of Labs has evolved since 2020. Looking ahead, Labs can play a pivotal role in addressing ongoing gaps and crises in Canada’s health system through building ‘relational infrastructure.’ Specifically, Labs can (1) act as connective tissue in a siloed system, (2) engage community partners in dialogue and collaborative processes to build bridges between health system actors, and (3) centre community voices in developing strategies and solutions through equitable co-design.