Objectives: Small enterprises have higher exposure to occupational hazards compared to larger enterprises and further, they have fewer resources to control the risks. In order to improve the working environment, development of efficient measures is therefore a major challenge for regulators and other stakeholders. The aim of this paper is to develop a systematic model for the design of tailored intervention programmes meeting the needs of small enterprises. Methods: An important challenge for the design process is the transfer of knowledge from one context to another. The concept of realist analysis can provide insight into mechanisms by which intervention knowledge can be transferred from one context to another. We use this theoretical approach to develop a design model. Results: The model consist of five steps: 1) Defining occupational health and safety challenges of the target group, 2) selecting methods to improve the working environment, 3) developing theories about mechanisms which motivate the target group, 4) analysing the specific context of the target group for small enterprise programmes including owner-management role, social relations, and the perception of the working environment, and 5) designing the intervention based on the preceding steps. We demonstrate how the design model can be applied in practice by the development of an intervention programme for small enterprises in the construction industry. Conclusion: The model provides a useful tool for a systematic design process. The model makes it transparent for both researchers and practitioners as to how existing knowledge can be used in the design of new intervention programmes.