We advance the judgement-based approach at the foundational level to establish cognitive microfoundations and boundary conditions as a formal theory of entrepreneurship – entrepreneurial judgement theory (EJT). We build upon philosophy’s concept of intentionality to define and conceptualise judgement as the determination and instigation of intentions. Entrepreneurship begins when, through entrepreneurial judgement, intentions are turned entrepreneurial, that is, towards the pursuit of new economic value, and ends when those intentions are turned away again. We elaborate the dynamics of this process, which includes cascading judgements across nested intentions. We conclude by distinguishing EJT from its close relative, entrepreneurial action theory, and by connecting entrepreneurial judgement more explicitly to contemporary psychology research.