Citizen science has proven to be a useful paradigm both to contribute to science and to increase the public understanding of science. Thus the connection between citizen science and schools offers an interesting approach to explore. However, a lot of questions and challenges remain unclear, such as the balance between scientific and educational goals. In this research, we explore how citizen science initiatives have been implemented in formal education contexts through a systematic literature review. The final aim is to identify relevant characteristics, define profiles of initiatives and offer future implications. Through the PRISMA Protocol, we have selected 46 published citizen science initiatives to analyse. Our findings show four different profiles of citizen science initiatives in schools: Students using science, Students helping science, Students learning science collecting data and Students learning science by acting as scientists. From the discussion of these profiles, we suggest some considerations for researchers and designers.