Scientific literacy is now seen as an essential component of informed citizenship and a key curriculum goal in many parts of the world. The relevant literature is vast and replete with a variety of definitions, descriptions, prescriptions, slogans and theoretical perspectives. It addresses not only formal education but also fields as diverse as hand-on science centres, museums, the print and broadcast media, science journalism, politics, medicine, film and drama. In this article, the author considers how the public understanding of science, as revealed by research, relates to scientific literacy in schools. Scientific literacy generally assumes more than knowledge of facts (DBIS, 2010). For example, the Program for International Student Assessment (PISA) defines scientific literacy as the ability to use scientific knowledge and processes to understand the natural world and to participate in decisions that affect it (OECD, 2007). As a result, an important component of the 2006 round of testing explored students' ability to acquire interpret and act upon evidence in a variety of personal and social contexts, such as health and the environment. Testing of this kind is difficult, not least because thinking scientifically requires cognitive processes that are common to many other forms of scholarly inquiry. In recent years, research attention has moved away from exploring how well citizens understand the concepts, processes and practices of science and towards developing a greater insight into how they engage with science and science-related issues. Nonetheless, for curriculum developers, scientific literacy remains a useful over-arching goal, capable of sustaining a variety of meanings and rationales and of generating a diverse range of curriculum initiatives.