abstract We review and develop a subjectivist theory of entrepreneurship that focuses on individuals, their knowledge, resources and skills, and the processes of discovery and creativity, which constitute the heart of entrepreneurship. First, we establish the fundamental importance of subjectivity in entrepreneurial discovery and creativity. Second, we build on Penrose (1959) to elaborate how entrepreneurs' perceptions and personal knowledge shape a firm's subjective productive opportunity set. Third, we explain that entrepreneurial perceptions and knowledge partly originate from entrepreneurs' experiences in specific business settings such as the firm, the management team, and the industry. Fourth, we highlight the causal connections between subjectivity in entrepreneurship and observed heterogeneity in firm-level economic performance. Lastly, we suggest directions for further advancing a subjectivist resource-based approach to future entrepreneurship research.