In this paper I attempt to develop a notion of responsibility (semantic responsibility) that is to the notion of belief what epistemic responsibility is to the notion of justification. 'Being semantically responsible' is shown to involve the fulfilment of cognitive duties which allow the agent to engage in the kind of reason-laden discourses which render her beliefs appropriately sensitive to correction. The concept of semantic responsibility suggests that the notion of belief found in contemporary philosophical debates about content implicitly encompasses radically different classes of beliefs. In what follows I make those different types explicit, and sketch some implications for naturalisation projects in semantics and for accou...