We are increasingly exposed to complex societal and technological problems. Qualified Science, Technology, Engineering and Mathematics (STEM) professionals are needed to solve these problems and cope with contemporary demands such as sustainable energy and efficient healthcare [1]. It is not surprising then that the World Economic Forum's Future of Jobs Report (2016) predicted a job gain in STEM fields for the following years [2]. However, we do not only need STEM professionals who can solve these problems. We also need people with a certain level of basic STEM literacy. All citizens, even non-STEM professionals, should have the skills and competences necessary to deal with the challenges of our information-based and highly technological society [3]. STEM-literacy, i.e., the awareness of the nature of science, technology, engineering, and mathematics, and the familiarity with fundamental concepts from each discipline, should be an educational priority for all students [3], [4].

Our rapidly changing society needs highly-qualified STEM professionals (experts in science, technology, engineering, and mathematics) to develop solutions to the problems it is facing. Many of the students who graduate from a STEM programme in secondary education, however, opt out of STEM when enrolling in higher education, often due to a loss of interest. To ensure sufficiently high and qualified enrolment in higher STEM education, we need to bridge this gap between secondary and higher STEM education by showing our youngsters the relevance of science and technology to their personal life and environment. To this end, the project STEM@school promoted and studied the idea of integrated STEM in secondary education in Flanders, Belgium. In integrated STEM education, learning contents from the separate STEM courses are linked in an authentic way, as they often are in our environmental challenges. This approach encourages students as well as their teachers to acquire a robust understanding of STEM concepts, and a creative, inquisitive, and collaborative mindset. For the design of integrated STEM curricula, STEM@school united secondary-school STEM teachers and university researchers. This article elaborates on the principles, opportunities and challenges of the design and implementation of these curricula and discusses their promising effects on students’ conceptual understanding and attitudes towards STEM subjects. The article concludes with tips and tricks to get started with integrated STEM education in secondary schools.