An increasing number of entrepreneurial ventures aim at developing viable business models for solving societal or ecological challenges. Such business models for sustainability (BMfS) build on reinforcing mechanisms of value creation and capture that allow to simultaneously achieve financial and sustainability objectives. To date, we do not know much about the successful design of such business models for new markets with highly uncertain dynamics. Hence, this research aims at advancing the understanding about two key characteristics of successful BMfSscalability and robustnessand their impact on performance of entrepreneurial BMfS in uncertain environments. Toward this aim, it uses simulation modelling of an entrepreneurial BMfS under different future scenarios. The simulation represents the case of Coursera, an entrepreneurial venture with the social mission of making high-quality education globally accessible through Massive Open Online Courses (MOOCs). Rooted in the literature on business models (for sustainability), innovation adoption and System Dynamics, the simulation model integrates the four value dimensions of BMfS and allows testing different hypotheses about its sustainable performance. The simulation experiments show that the business model is scalable, but not sustainable in a scenario of high competition. We discuss the implications of the simulation results for the effective design of entrepreneurial BMfS.