AbstractAdvances in green stormwater infrastructure (GSI) and extensive implementation of GSI in urban areas warrant further research by municipalities on different aspects of GSI systems (e.g., planning, modeling, design, construction, monitoring, and maintenance) to enhance operational efficiencies, reduce the overall cost of construction and maintenance, and increase the resilience of these systems. However, because of a limited budget and resources for GSI research at the municipal level, a multicriteria decision analysis (MCDA) method is needed to aid the prioritization of research needs using an array of technical, economic, social, and environmental considerations (criteria). To address this need, a hybrid, multicriteria, group decision making approach was used to inform the prioritization of GSI research needs. In this approach, the relative weights of decision criteria are determined using the Delphi method on the basis of input from multiple decision makers (DMs). Additionally, ranking the research topics is performed using a hierarchical simple additive weighting (SAW) method. The application of the hybrid MCDA method was shown in prioritizing GSI research needs to support a division within the Philadelphia Water Department’s GSI program for which a long- and short-list of GSI research topics, containing 67 and 13 items, respectively, and a hierarchy of multidisciplinary decision criteria, containing 39 items, were developed. Sensitivity analyses were conducted to partially address the uncertainties in the decision-making process. The presented method is simple (applicable to real case studies) yet systematic (adjustable in different geographic locations) and supports group decision making, making it suitable for adoption by urban GSI entities as a decision-support tool for prioritizing existing needs and developing future roadmaps for GSI research.