With the economic and technological developments of Asian countries in the last two decades, nurturing individuals' capabilities for logical thinking and problem solving have become one of the major foci of secondary education. Being a core subject for developing the fundamental ability of high school students towards systematic and organized ways of thinking, mathematics is no longer a requirement only for students who are going to study science or engineering majors in university but has become a common core subject for whole-person education. In this chapter, we shall investigate the recent development of high school mathematics curricula in Hong Kong, South Korea and Singapore, in coping with the change. Copyright © 2018 selection and editorial matter, Kerry J. Kennedy and John Chi-Kin Lee; individual chapters, the contributors.