As dangerous climate change looms, decision-makers are increasingly realising that societies will need to adapt to this threat as well as mitigate against it. Green infrastructure (GI) is increasingly seen as an ideal climate change adaptation policy response. However, with this research the authors identify a number of crucial knowledge gaps within GI and, consequently, call for caution and for a concerted effort to understand the concept and what it can really deliver. GI has risen to prominence in a range of policy areas in large part due to its perceived ability to produce multiple benefits simultaneously, termed ‘multifunctionality’. This characteristic strengthens the political appeal of the policy in question at a time when environmental issues have slipped down political agendas. Multifunctionality, however, brings its own set of new challenges that should be evaluated fully before the policy is implemented. This research takes important first steps to developing a critical understanding of what is achievable within GI’s capacity. It focuses on one of GI’s single objectives, namely climate change adaptation, to focus the analysis of how current obstacles in applying GI’s multifunctionality could lead to the ineffective delivery of its objective. By drawing on expert opinion from government officials and representatives from the private, non-government organisation (NGO) and academic sectors, this research questions GI’s ability to be effectively ‘multifunctional’ with an inconsistent definition at its core, deficiencies in its understanding and conflicts within its governance. In light of these observations, the authors then reflect on the judiciousness of applying GI to achieve the other objectives it has also been charged with delivering.