The limitations of labour law and its implementation in Vietnam have been identified by scholars as the main reasons for the persistence of factory strikes, yet there has been little analysis concerning how workers themselves perceive the labour law and how law matters in workers’ resistance to abusive practices. This paper explores how workers’ ideas of justice are shaped by, on the one hand, legal language and the values embedded in that language, and on the other, experiences and discourse that differ from those language and values. From interviews and workers’ letters in Đồng Nai Province, I demonstrate that labour law is only one factor shaping workers’ views of what is fair. The way workers turn (or do not turn) to law depends on their perceptions of the relationship between law and the morality of workplace behaviour. These perceptions, in turn, are constructed through their experiences at work, and are shaped also by cultural norms and socialist ideology.