Scientific and mathematical education has expanded in most education systems in the twentieth century, especially in the second half when there emerged the perception among policy-makers that science and technology were essential to a flourishing economy and to individual opportunity. Scotland provides a useful case study of the expansion, for two reasons. One is that it has included natural science in its emerging secondary-school curriculum at an early period by international standards, well before the middle of the century. That inclusion was carried over into the new curricula at the mid-secondary level, which aimed to cater for all students when the public sector of secondary schooling became non-selective after the 1960s. So Scotland is a test case of whether a gradually democratising system of secondary schooling could widen access to science and mathematics, and of whether and how changes at the school level contributed to the expansion of school-leaver entry to science in higher education. The other reason why the Scottish case is potentially revealing is a unique series of surveys of school students that cover the whole of the second half of the century.