Two important philosophical questions about assertion concern its nature and normativity. This article defends the optimism about the constitutive norm account of assertion and sets out a constitutivity thesis that is much more modest than that proposed by Timothy Williamson. It starts by looking at the extant objections to Williamson’s Knowledge Account of Assertion (KAA) and argues that they fail to hit their target in virtue of imposing implausible conditions on engaging in norm-constituted activities. Second, it makes a similar proposal and shows how it does better than the competition. It suggests that Knowledge Norm of Assertion (KNA) is not constitutive of the speech act of assertion in the same way in which rules of games are consti...