In recent years, MOOCs have become firmly established as valid e-learning environments and, as such, have been developed by many universities using different types of platform. Given the voluntary nature of MOOC enrollment, motivation is crucial to our understanding of why students register for and complete these courses. The present study explores the motivations that characterize MOOC participants and how they relate to technology acceptance variables (data collected via questionnaires) and participation variables (observational data collected via the platform). Our results indicate that students show exceptionally high levels of intrinsic motivation. However, extrinsic motivation also plays a relevant role, suggesting that the two are not mutually exclusive. Although only intrinsic motivation appears to be systematically associated with differences in technology acceptance, both are associated with differences in participation, but in contrasting ways. Our results provide insights that will enable us to improve MOOC design in order to enhance participant satisfaction, particularly when different sources of motivation are involved. Future research based on the modeling of technology acceptance and participation will also benefit from this study.