From the publication of the first two cantos of Don Juan in 1819, the poem’s legal status was in doubt. Although never found blasphemous or seditious in a criminal court, Byron’s copyright in Don Juan was not upheld by the civil courts, owing to the possibility that the poem might be ‘injurious’ to the public. Alongside these courtroom debates, Byron and his poetry came under increasingly intense scrutiny before the figurative ‘tribunal of the public’, in periodicals and newspapers. Reviewers and commentators appraised Don Juan in the vocabulary of the criminal law, assuming the roles of advocate, jury and judge. This article analyses some of these legal and quasi-legal attacks, and investigates how Byron engaged with them. Don Juan, I propose, bears traces of the legal pressures Byron faced, absorbing the threat of criminal prosecution and exploring the question of what an oppositional statement of self-defence might look like.