A transition towards a circular food system whereby the agricultural food chain changes from a linear production chain to a more circular system with minimal unnecessary losses could be the answer to a range of global challenges, such as climate change, diminished water quality and biodiversity, and food insecurity. This paper focuses on behavioural factors and external conditions that influence the decisions of Dutch farmers in the transition towards circular agriculture (CA). This study consists of a literature review, 13 semi-structured, qualitative, in-depth interviews with farmers who contributed to CA and a survey of 429 farmers representing a range of farm types and sectors. Structural Equation Modelling showed that attitude and intrinsic and extrinsic motivation are significant predictors of the intention to take measures that contribute to CA, behavioural beliefs, perceived risk and uncertainty, and intrinsic and extrinsic motivation are all significant predictors of attitude; and intention, perceived behavioural control and subjective knowledge are significant predictors of the relative number of farmers that contribute to CA. Univariate analyses showed that farmers who took more measures that contribute to CA were motivated more by social and environmental values, while farmers who took fewer measures that contribute to CA were motivated more by economic values. In the in-depth interviews, knowledge, resistance from the environment and unsuitable legislation were the barriers mentioned most often. These insights may prove helpful for policymakers and other advisors who influence farmers’ decision making regarding CA. Some examples of what these insights can be used for include: persuasive communication aimed at influencing motivations, beliefs and attitudes; framing directed towards motivating pro-environmental and social values to increase intrinsic motivation; economic incentives to increase extrinsic motivation; providing information for decreasing farmers’ perception of risk and uncertainty, ...