Cities are facing more extreme climates and weather events. This requires changes in the way cities are planned and designed. Blue-Green Infrastructure (BGI) is increasingly recognized to guide the transition to climate resilient cities. BGI is founded in urban water management but has emerged as a complementary type of infrastructure because it can provide multiple benefits. To advance the integration of BGI in the urban landscape, Planning Support Systems (PSS) have proven their merit. PSS are any kind of digital tool for support in planning processes. However, PSS are not used much in urban planning. This could have multiple reasons, but it referred to the implementation gap. The gap suggests a mismatch between PSS supply and demand. The demand is set by the practitioners of PSSs, the urban planners. Most effort in closing the gap is with research on improving the technical specifications of PSS. The challenges urban planners are facing in implementing BGI hasn’t been carefully studied. To improve the uptake of PSS for BGI implementation, this thesis evaluated a prototype PSS, studied on the case of the municipality of Amsterdam. Next to the conceptualization of BGI and PSS, the objectives were: to understand urban planning processes; to determine the challenges for BGI implementation; and to find opportunities for PSS to address these challenges. This thesis conceptualizes BGI and PSS in the perspective socio-technical solutions in the transition to sustainable urban development. The planning processes and related challenges are studied by means of semi-structured in-depth interviews with 9 urban planners of the municipality of Amsterdam. Five of them participated in a focus group in which the prototype PSS was evaluated. Amsterdam constructed four main planning processes with which it aims to apply an integrated approach to the implementation of BGI. The main challenges urban planners are struggling with multi-objective planning required in the increasingly complex urban landscape; translating abstract and contradictory policy into practice without classification and standardized BGI measures; and collaborating to obtain the integrated approach. During the focus group, the participants listed multi-objective planning and supporting collaborative processes as most appropriate opportunities for the protype PSS. The use of PSS is highly dependent on the balance of technical and supportive functions. This thesis provides insights for PSS-developers on how to meet the demand of urban planners. With more useful PSS the transition for sustainable urban development can be accelerated.