The opportunity actualization perspective has recently gained attention as a key framework for exploring entrepreneurial opportunity. The perspective’s theorizing, however, predominantly focuses on profit-driven opportunities, limiting its applicability across the spectrum of entrepreneurial behavior. To broaden applicability, we examine how entrepreneurs motivated by social and economic considerations form their opportunity beliefs. We use a qualitative research approach that combines think-aloud protocols and semi-structured interviews with 24 impact entrepreneurs. Our findings allow us to develop a holistic model of social business opportunity belief formation, incorporating market and non-economic considerations, emphasizing the role of non-market stakeholders. We derive important implications for both theory and practice.