The dissertation examines factors influencing nonprofit organizations' contribution to collaborative governance for climate change adaptation and nonprofit roles in the collaboration. Why an organization collaborates with others has long been a concern of scholars. However, in a majority of empirical studies, collaboration has been considered as a dichotomous concept. To fill the gap, this study considers organizations' contribution to collaboration, i.e., collaboration level in terms of power, joint activities, human resource, funding, and information sharing. To understand contribution of nonprofits to collaboration for climate change adaptation, this research employs the institutional collective action framework suggesting that organizations work together when expected benefits are greater than collaborative risks. Survey data from 101 nonprofit private organizations (beyoungri mingan danche) in South Korea, which are legally defined in the Assistance for Nonprofit, Nongovernmental Organizations Act, are analyzed. Finding is that government funding and social relationship are strongly associated with nonprofit contribution to collaboration, highlighting that the financial stability of nonprofit organizations and mutual trust among entities based on routine interaction are critical motives for nonprofit collaboration. Finding also reveals that Korean nonprofits mainly play a role as social capital creators in climate change adaptation. The finding also highlights that Sang Bu Sang Jo (相扶相助) among community members is a key concept to encourage nonprofit engagement in climate change adaptation in the Korean context.