Ecosystem-based Adaptation (EbA) is increasingly being advocated as a climate adaptation approach that can deliver multiple benefits to communities. EbA scholarship argues that community-based projects can strengthen those ecosystems that deliver critical services to communities and in doing so enhance community resilience. In particular, the inclusion of indigenous and traditional knowledge (ITK) into community-based EbA projects is positioned as critical to successful climate adaptation. Yet, there is surprisingly little investigation into how ITK is being defined and incorporated into EbA initiatives. This paper critically reviews EbA literature and provides empirical examples from Vanuatu and Samoa to demonstrate the different ways ITK relates to EbA projects. We find that there is widespread recognition that ITK is important for indigenous and local communities and can be employed successfully in EbA. However, this recognition is more aspirational than practical and is not being necessarily translated into ITK-informed or ITK-driven EbA projects. ITK should not be conceptualized simply as a collection of local environmental information that is integrated with Western scientific knowledge. Instead, ITK is part of nested knowledge systems (information–practices–worldviews) of indigenous peoples. This knowledge includes local natural resource management, sociocultural governance structures, social norms, spiritual beliefs, and historical and contemporary experiences of colonial dispossession and marginalization. At present, most EbA projects focus on the provision of information to main decision-makers only; however, since ITK is held collectively, it is essential that entire communities are included in ITK EbA projects. There is a huge potential for researchers and ITK holders to coproduce knowledge that would be best placed to drive climate adaptation in a changing world.