My PhD thesis examines the experience of girls who attended missionary middle schools in East China 1917-1952. I look at four schools across three cities: In Shanghai, St. Mary’s founded by the American Episcopal Church in 1881 and McTyeire, an American Methodist school founded in 1892. In Ningbo and Hangzhou, I focus on two union schools for girls established by the North American Presbyterian and Baptist Missions; Riverside Academy established in Ningbo in 1923 and Hongdao, established in Hangzhou in 1912. Using pupils’ writings in their school magazines, alongside interviews with ex-pupils, missionary reports and newspaper sources, the thesis seeks to understand missionary school girls’ agency in shaping and influencing new forms of modernity emerging in early twentieth century China. How did they navigate their school environment and negotiate their identities as both Christian and Chinese within an increasingly nationalistic setting, characterised by anti-imperialist and anti-Christian movements in the 1920s? How did mission school pupils use a gendered Christian rhetoric to fashion their identities within debates about women’s roles in a newly emerging public sphere in the Republican era? What can the experience of missionary school girls tell us about the relationship between Christianity, Communism and the Women’s Movement in China? This research breaks new ground by examining the missionary enterprise from the point of view of pupils who attended missionary schools rather than from the missionary perspective. By placing the experience of pupils at the centre of enquiry, we can see how Chinese women were active agents in the creation of a transnational modernity in treaty port East China. I argue that the hybrid cultural environment at missionary schools unintentionally created a free space or ‘laboratory’ where girls could experiment with more fluid gender identities, which challenged traditional binaries and allowed them to forge new conceptions of Chinese womanhood.