Complex social and environmental issues call for broader collaboration across different sectors so as to instigate transformative social change. While previous scholars have emphasized the role of non-governmental organizations (NGOs) in facilitating social change, they have not provided a nuanced assessment of NGOs' different roles. We use the Poverty and Employment Precarity in Southern Ontario (PEPSO) research partnership as a study case and explore NGO partners' different roles in a large cross-sector social partnership (CSSP). By interviewing 12 NGO partners and 4 non-NGO partners involved in the PEPSO research partnership, our research results show that NGOs primarily have 10 roles in a CSSP. They include enabling roles such as consultant, capacity builder, analyst, and funder; coordinating roles such as broker and communicator; and facilitating roles such as initiator, leader, advocate, and monitor. These roles allow NGOs to fulfil their duties to make substantial contributions to a CSSP. © 2018 by the authors.