Ecosystem-based (EB) approaches have been strongly promoted in various international environmental and development processes. As a result, they are gaining increasing attention among development practitioners, policymakers and researchers. A review of G20 national adaptation plans and related strategies revealed that member countries have recognized EB approaches, which they expect can generate a wide range of benefits. Some G20 countries have identified indicators and targets and developed guidelines for mainstreaming, as well as allocating modest funding for implementation of EB approaches. G20 countries still face significant challenges, however, to promote EB approaches associated with mainstreaming, financing, monitoring and evaluation, and institutional and policy bottlenecks. These bottlenecks are related to capacity and attitudinal factors, and insufficient research and evidence on the effectiveness of the EB approach. To enhance mainstreaming and understand costs and benefits in the short to long term, it is important that research, and monitoring and evaluation efforts collect tangible evidence on the effectiveness of EB approaches. Engaging the private sector could help countries to bridge the gap between needs and available finances, while also building the capacities of governments. Tax benefits, concessional loans, and subsidies can provide the necessary incentives for implementing EB approaches through public-private partnerships. Countries can put in place facilitative institutional and policy mechanisms for EB approaches. These can include technical advisory bodies to guide ministries on mainstreaming, guidelines for policymakers and practitioners, and mandates for organizations to employ EB approaches. Project financing guidelines can be designed to provide the impetus for project formulators and implementers to consider EB approaches. Governments can set an example by integrating EB approaches into their own operations. Mechanisms under the G20, such as the Climate Sustainability Working Group, can provide a means for countries to exchange experiences and technologies to facilitate the scaling up of EB approaches.