Risk is always present in people's lives: diseases, new technologies, socio-scientific issues (SSIs) such as climate change, and advances in medicine--to name just a few examples--all carry risks. To be able to navigate risks in everyday life, as well as to participate in social debate on risk-related issues, students need to develop risk competence. Science education can be a powerful tool in supporting students' risk competence, which is an important component of scientific literacy. As there are different definitions of risk within the scientific community, the aims of this article are (1) to review the literature on two major theoretical frameworks for conceptualising risk, the realist, and the constructivist paradigms of risk and (2) to connect both in order to suggest a working definition of what can be understood as risk competence in science instruction.