The intrapreneurial behavior of employees has become of strategic importance for the performance of organizations. However, the literature on intrapreneurship is dispersed and in need of an integrated overview of the characteristics and behaviors of intrapreneurial employees. Based on a systematic literature review, we propose a new definition of intrapreneurship that emphasizes its multilevel nature. Moreover, we propose a comprehensive model of intrapreneurship in which we integrate the new definition, dimensions, and determinants applicable to individual employees. We find that innovativeness, proactiveness, risk-taking, opportunity recognition / exploitation and internal / external networking are important behavioral dimensions of intrapreneurship. A certain skillset, a perception of their own capabilities, personal knowledge, past experience, the relation with the organization, motivation, satisfaction and intention are the determinants of intrapreneurial behavior that we derived from the literature review. Based on our results and an integrated model of intrapreneurship, we suggest a number of future research directions.