This chapter examines how a transnational network of European sanitary, medical and educational experts helped define the contour of architectural reform and hygiene curriculum in Hong Kong from 1901 to 1941. Travelling back and forth between Hong Kong and the wider British imperial world, these colonial experts brought new approaches to public health that subsequently shaped practices in Hong Kong schools. As architectural reform, hygiene education and medical inspection were most rigorously carried out in the state-sponsored English schools (English-medium) that educated a multiracial but predominantly Chinese middle-class cohort, this strand of schools became the prime site where sanitary innovations and hygiene curriculum materialised. Just as imperial preoccupation with youth health drew the spaces of the classroom, dormitory, and school playground into the discourse of hygiene to create a new typology of school architecture, it simultaneously stratified a class structure in Chinese society. School health, in turn, functioned as an important means to enact new class and gender dynamics in Hong Kong in the early 20th century, entwining with the rise of Chinese bourgeoisies and female professionals, as well as eugenic thought that reframed the health of Hong Kong youth as directly connected with the future of the British empire. Copyright © 2024 selection and editorial matter, Kellie Burns and Helen Proctor; individual chapters, the contributors.