By relying on the case of São Paulo, this article seeks to develop a critical look at urban farming and its potential for contributing to food justice. While this activity constitutes a means of subsistence for urban communities, it is also underlain by principles relating to land ownership, which tend to divert attention from its primary role in food systems. There is an important need first to fight against land inequalities and bad housing in São Paulo, before considering urban farming as a lever for food justice. For this study, I made use of qualitative surveys carried out between 2018 and 2022 in São Paulo, during which I conducted 118 interviews with farmers, consumers, shopkeepers, associations and politico-administrative institutions. My results show at first a socio-economic dichotomy between well-off city dwellers who use community gardens and farmers who practise urban farming on the margins of the city. I maintain that the issue of food justice affects the latter and is filtered through a policy of institutional action and visibility. In conclusion, I argue that urban farming is a potential lever for food justice which is still highly constrained by inequalities and land speculation in São Paulo.