Teacher unions are working in challenging times. Building power is important for teacher unions to resist neoliberal reforms that have aimed to restructure school education and weaken collective organisation. Yet we have few understandings of the democratisation project that teacher unions have engaged in to build and renew internal power in this environment. Drawing upon insights from a successful case study of teacher union democracy in Australia, this article highlights the importance of forging member-led and coordinated democratic structures and processes that foster collective voice as well as engaging in ongoing renewal in order to build and maintain internal power in a neoliberal climate.