Since Chile returned to democracy in 1990, centre-left governments have tried to reform the provisions on collective bargaining, strikes and unions established by the Pinochet dictatorship. Between 2015 and 2016 President Michelle Bachelet made the latest attempt to reform them. Despite favourable conditions, the changes were modest. This article explains why this is so. Drawing upon the notion of ‘associational power’ and through comparisons with labour reforms in Argentina, Brazil and Uruguay, this article suggests that the imbalance between workers’ and employers’ collective power is key for explaining why pro-labour reforms fail.