ABSTRACT. The focus of the Special Feature on "Multicriteria assessment of food system sustainability" is on the complex challenges of making and communicating overall assessments of food systems sustainability based on multiple and varied criteria. Four papers concern the choice and development of appropriate tools for making multicriteria sustainability assessments that handle built-in methodological conflicts and trade-offs between different assessment objectives. They underscore the value of linking diverse methods and tools, or nesting and stepping their deployment, to help build resilience and sustainability. They conclude that there is no one tool, one framework, or one indicator set that is appropriate for the different purposes and contexts of sustainability assessment. The process of creating the assessment framework also emerges as important: if the key stakeholders are not given a responsible and full role in the development of any assessment tool, it is less likely to be fit for their purpose and they are unlikely to take ownership or have confidence in it. Six other papers reflect on more fundamental considerations of how assessments are based in different scientific perspectives and on the role of values, motivation, and trust in relation to assessments in the development of more sustainable food systems. They recommend a radical break with the tradition of conducting multicriteria assessment from one hegemonic perspective to considering multiple perspectives. Collectively the contributions to this Special Feature identify three main challenges for improved multicriteria assessment of food system sustainability: (i) how to balance different types of knowledge to avoid that the most wellknown, precise, or easiest to measure dimensions of sustainability gets the most weight; (ii) how to expose the values in assessment tools and choices to allow evaluation of how they relate to the ethical principles of sustainable food systems, to societal goals, and to the interests of different stakeholders; and (iii) how to enable communication in such a way that the assessments can effectively contribute to the development of more sustainable food systems by facilitating a mutual learning process between researchers and stakeholders. The wider question of how to get from assessment to transformation goes across all three challenges. We strongly recommend future research on the strengths, weaknesses, and complementarities of taking a values-based rather than a performancebased approach to promoting the resilience and sustainability of coupled ecological, economic, and social systems for ensuring food security and agroecosystem health in the coming millennium.