This article provides a nuanced understanding of various societal actors who work towards enhancing labour protection in contemporary China, which are labelled as “labour watchdogs”. Based on extensive field research between 2008 and 2012, the authors offer an analysis of labour watchdogs and their activities in Nanjing. Labour watchdogs complement formal enforcement by the labour bureaucracy and the All-China Federation of Trade Unions (ACFTU); facilitate workers’ bottom-up legal activism; and put pressure on employers directly and indirectly to improve working conditions. This article shows that labour watchdogs have an unintended yet notable complementary effect on labour protection in China, a country that lacks an independent, strong labour movement.