Building on the indicator frameworks of the Aichi Biodiversity Targets, the SDGs and other multi-country data sources, this report presents a preliminary set of indicators that could be considered for further use to help monitor and evaluate biodiversity mainstreaming efforts in a more consistent manner. This includes indicators across the range of response indicators, namely inputs (e.g. finance), processes (e.g. establishment of inter-ministerial committees), outputs (e.g. national assessments and other studies), outcomes (e.g. new or more ambitious policies) and impacts (changes in the state of biodiversity and ecosystem services). Based on this work, as well as previous OECD efforts to assess mainstreaming in the context of green growth, climate change and development co-operation, there are five main areas of action needed by policy makers and decision makers to promote effective mainstreaming of biodiversity and development. This commitment should also be reflected in NBSAPs and national/sector development policies, supported by policy coherence across legislative and policy frameworks.