According to commitment accounts of assertion, asserting is committing oneself to something’s being the case, where such commitment is understood in terms of norms governing a social practice. Sections 1 and 2 of this chapter elaborate and compare two types of commitment account, liability accounts (associated with C. S. Peirce) and dialectical norm accounts (associated with Robert Brandom), concluding that the latter are more defensible. Section 3 argues that both types possess an advantage over rival normative accounts of assertion in that they needn’t presuppose any notion of an assertion’s correctness. Section 4 shows how dialectical norm accounts can explain relations between assertion and truth. Section 5 sets forth objections that have been raised against commitment accounts, and argues that responses are available on behalf of dialectical norm accounts. Section 6 proposes that a liberalized dialectical norm account can illuminate phenomena sometimes seen as supporting truth relativism.