Green infrastructure (GI) has emerged as a strategic landscape approach to aid in creating more sustainable communities that benefit both people and wildlife. Despite the well-known social, economic and environmental benefits of GI in managing stormwater, many municipalities have been slow to adopt GI. To understand some of the factors impeding GI adoption this study conducted a comparative case-study analysis between two municipalities and two Conservation Authorities in southern Ontario with a focus on stormwater management (SWM). Interviews were conducted with four key informants and were analyzed using coding and theming. Results indicate a number of significant barriers including: a lack of experience by contractors in constructing GI projects, maintenance costs and complexities of GI, and the need for a cultural modernization within municipalities. The knowledge revealed through this study can benefit municipalities in overcoming barriers similarly experienced in municipalities in southern Ontario.