The Convention on Biological Diversity (CBD) defines Ecosystem-Based Adaptation (EBA) as "the use of biodiversity and ecosystem services as part of an overall adaptation strategy to help people to adapt to the adverse effects of climate change". Climate change is happening at an unprecedented rate and impacting a large number of people globally. The need for adaptation efforts has never been so urgent. In particular, ecosystembased adaptation approaches have proved to provide flexible, cost effective and broadly applicable alternatives for reducing the impacts of climate change, and as such are a critical tool at the disposal of adaptation planners for tackling the threats that climate change poses to people's lives and livelihoods across the globe. In this paper, the evolution of the EBA concept is presented; EBA definition, advantages and principles are summarized; EBA tools and methods are introduced; and lessons learned from EBA case studies are explored. Furthermore, challenges of EBA are discussed.