Today entrepreneurship is recognized as a psychological phenomenon, in which cognitive, emotional and behavioral factors help a person to see an opportunity, face setbacks and achieve a long-term and sustainable success in business. Although financial, strategic and environmental factors have been the focus of research in the past, modern research literature focuses on entrepreneurial psychological resources such as entrepreneurial resilience, self-efficacy, emotional intelligence, risk tolerance and psychological capital (PsyCap), as key predictors of entrepreneurial effectiveness and sustainability. Based on Social Cognitive Theory, Psychological Capital Theory, and related theories, this chapter says that success is not only about external resources but also about the ability of the entrepreneurs to handle uncertainty, overcome failures, control emotions and have confidence in difficult situations. We build an integrated conceptual framework that connects psychological resources with entrepreneurial cognition, behavior and sustainable outcomes and discuss implications for entrepreneurship education, entrepreneurship development and policy. The chapter ends with future research directions that combine psychological, behavioural and contextual viewpoints.