Opportunity evaluation is an important concept in entrepreneurship, central to our understanding of how individuals evaluate specific opportunities, develop entrepreneurial intentions and (possibly) engage in entrepreneurial behavior. Existing understandings of opportunity evaluation tend to adopt a cognitive-centric approach. We build on the trilogy of the mind theory and the attitude literature from psychology to develop a new construct, opportunity attitude, which integrates cognition, affect and conation as a tri-component construct. This model regards opportunity evaluation as a dynamic process tending towards congruence of the cognitive, affective and conative components of mind. Importantly, it does not assume primacy of cognition, but allows for circumstances where affect or conation may dominate attitude formation or change. This conceptualization provides a more complete account of the way in which entrepreneurs evaluate entrepreneurial opportunities. Moreover, the interaction between the three attitude components provides a foundation for better understanding both the formation of an individual’s attitude toward an entrepreneurial opportunity and changes over time. Mechanisms underlying these attitude formation and change processes are identified and discussed.