There have been calls for greater inclusion of Indigenous and local knowledge (ILK) in applied ecosystems research and ecological assessments. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment (GA) is the first global scale assessment to systematically engage with ILK and issues of concern to Indigenous peoples and local communities (IPLC). In this paper, we review and reflect on how the GA worked with ILK and lessons learned. The GA engaged in critical evaluation and synthesis of existing evidence from multiple sources, using several deliberative steps: having specific authors and questions focus on ILK; integrating inputs from ILK across all chapters; organizing dialogue workshops; issuing calls for contributions to identify other forms and systems of knowledge; and encouraging IPLC to be key stakeholders and contributors. We identify content areas where attention to ILK was particularly important for questions in applied ecology. These include: (a) enriching understandings of nature and its contributions to people, including ecosystem services; (b) assisting in assessing and monitoring ecosystem change; (c) contributing to international targets and scenario development to achieve global goals like the Aichi Biodiversity Targets and the Sustainable Development Goals and (d) generating inclusive and policy-relevant options for people and nature. However, challenges in engaging different knowledge systems were also encountered. Policy implications. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment (GA) demonstrated the importance of Indigenous peoples and local communities (IPLC) to global biodiversity conservation and ecosystem management. Initiatives seeking to engage Indigenous and local knowledge (ILK) can learn from the experience of the GA. Successfully bringing ILK into assessment processes and policy arenas requires a deliberate framework and approach from the start that facilitates recognition of different knowledge systems, identifies questions relevant at various scales, mobilizes funding and recognizes time required and engages networks of stakeholders with diverse worldviews. In turn, fostering inclusion of ILK and partnering with IPLC can help future assessments understand how natural and cultural systems co-produce each other, identify trends of change through diverse biocultural indicators and improve sustainable development goals and policies.