<p>This essay intends to reflect on recent research regarding mathematics teacher expertise from a cultural perspective. First, the essay conceptualises and describes the characteristics of mathematics teacher expertise in East Asia. The expertise of mathematics teachers in the East Asian context is holistically characterised as emphasising deep content knowledge, pedagogical flexibility, research capability, mentoring skills, and moral roles—qualities that have been shaped by Confucian traditions and institutionalised professional development structures. Such type of expertise in mathematics teaching allows teachers to provide instruction in a flexible and coherent way, balancing mastery of mathematics knowledge, development of students’ mathematics interests and motivations, and development of higher-order thinking skills. The essay then identifies topics that should be addressed by future research, including comprehensive frameworks for mathematics teacher expertise, instruments to effectively measure mathematics teacher expertise, and international collaborations to disentangle cultural and universal aspects of mathematics teacher expertise and how mathematics teacher expertise influences the teaching and learning of mathematics. The essay concludes with reflection on the cultural dependency of teacher expertise by a commentary and a rejoinder, pointing out cultural differences between East Asian and Western conceptions of mathematics teacher expertise.</p>