The study of childhood and youth in modern China features few investigations that make engagement with personal documents by young people their focus. In order to understand how images of childhood and youth constructed by adults affected juvenile subjectivity, it is necessary to begin exploring how young people in China expressed themselves. This article first highlights the importance of youth in the Republican culture of mass education, when new opportunities for juvenile self-expression emerged. The success of the Northern Expedition, led by the Chinese Nationalist Party (Guomindang [GMD]), accelerated the spread of instructions for and publication of young people’s personal accounts. Finally, the article examines young people’s diaries, letters, and autobiographies (zizhuan) during the Nationalist period to argue for a greater emphasis on the contribution of children and adolescents to the conceptualization of youth, and the unique image of “modern China” that their personal documents reveal.