The theory of planned behaviour is a theory originating from psychology. Over time, the theory has been applied to a variety of research areas. In business administration, the theory is used to gain insight into the ethical behaviour of managers, the adoption of new products and entrepreneurship. The family business context is a specific context, in which the family has a strong influence on the strategic decisions of the business. Current application of the theory of planned behaviour in family business research focuses on succession. The main level of analysis in this research is the individual. To gain a deeper understanding of family business decision making, a theory is required that can be applied at multiple levels. In this chapter, it is argued that application of the theory of planned behaviour at the family and business level is possible because interaction between individuals results in the creation of common beliefs and intentions. This opens up future research avenues using the theory of planned behaviour, such as corporate entrepreneurship and the internationalisation of family firms. Keywords: theory of planned behaviour, family business, strategic decision making, multi-level analysis, corporate entrepreneurship, internationalisation.