Abstract Background Natural flood management (NFM) measures seek to protect, enhance, emulate, or restore the natural function of rivers as part of approaches to flood risk management (FRM). While there is agreement in both academic and practice/policy literature that NFM, in a general sense, should be part of a holistic FRM strategy to address current and future flood risk, the specifics of how to consistently implement NFM successfully in practice are less well known. This is particularly acute for practitioners in the UK given the nature of the UK’s biophysical and socio-political context. There is a recognition that existing reviews of NFM effectiveness in the UK tend to focus on the natural science basis and it is unclear how studies account for climate change. Further, reviews tend to focus only on UK studies. This systematic map aims to highlight the way in which existing NFM studies, from different disciplinary backgrounds and across Europe, evaluate effectiveness, and the extent to which they account for climate change. This knowledge can help to make recommendations for future areas of research where the multiple issues around understanding effectiveness can be synthesised, and where climate change is systematically taken into account. Methods This systematic map protocol addresses the following question: what approaches exist to evaluate the effectiveness of UK-relevant natural flood management measures? The protocol details the methodology that will be used to conduct a systematic map of the range of peer-reviewed journal papers, policy documents, guidance, and other forms of grey literature which currently exist on NFM to give an overview on the way in which the effectiveness of NFM is conceived. The methods detail the search strategy employed for gathering items across the peer-reviewed academic literature and grey literature. Additionally, the methods outline how the reviewers will approach article screening, and the eligibility criteria to include/exclude articles. The methods section also details the steps taken to ensure consistency across all reviewers, the data coding strategy, and methods for presenting the final systematic map. Together, the methods employed will help to identify current knowledge gaps, and will enable recommendations to be made for future research.