One of the central theses in contemporary jurisprudence is that law is grounded in a social practice. It is far from being clear, however, what the characteristics of this practice would be. Starting from the discussion of the social practice thesis recently provided by Carlos Bernal-Pulido, this article critically considers whether the practice at the foundation of law can be seen as a form of joint action based upon collective intentionality and common knowledge. The paper reconstructs the idea of law as a social practice in the works of John Austin, Herbert Hart and Scott Shapiro, and shows that an accurate reading of these works leads us to cast doubt on the persuasiveness of Bernal-Pulido’s proposal. The practice at the foundation of law, if any, cannot be seen as a form of joint action without making several aspects of law puzzling or unaccountable. Finally, the article tries to shed some light on the contemporary debate about the normativity of law by distinguishing the different theoretical problems that this debate actually tackles.