This work has four aims: (i) to provide an overview of the current debate about the semantics of knowledge attributions, i.e. sentences of the form ⌜S knows that Φ⌝; (ii) to ground the debate in a single semantic-pragmatic framework; (iii) to identify a methodology for describing the semantics of knowledge attributions; (iv) to go some way towards describing the semantics of knowledge attributions in light of this methodology, and in particular to defend moderate invariantist semantics against its main current rivals. Aims (i) and (ii) are largely clarificatory; in §1 I set out a single semantic-pragmatic framework and over the course of this work show that it can be modified to explain and distinguish the various theories of the semantics of knowledge attributions currently on offer. Aim (iii) is also met in §1. I argue that a theory of the semantics of knowledge attributions T must be able to account for at least some ordinary speakers' intuitions about the felicity or infelicity of utterances of the sentence ⌜S knows that Φ⌝ (felicity intuitions) purely in terms of its semantics. I also identify a number of theoretical considerations about knowledge and argue that if T conflicts with any one of these considerations, we should presume that T is false. Aim (iv) is met over the course of this work. According to moderate invariantism ⌜S knows that Φ⌝ is true if and only if S confidently believes the proposition expressed by , this proposition is true and S's epistemic position with respect to this proposition meets a moderately high epistemic standard. In §§2 - 5 I argue that the main current rivals to moderate invariantism - attributor contextualism, contrastivism, subject-sensitive invariantism and assessor relativism - conflict with at least one of the theoretical considerations identified in §1. In §6 I argue that moderate invariantism accounts for some ordinary speakers' felicity intuitions purely in terms of the semantics of ⌜S knows that Φ⌝; I also argue that it is consistent with all of the theoretical considerations identified in §1. Moreover, in §§2 - 6 I argue that no theory is capable of accounting for all felicity intuitions purely in terms of the semantics of ⌜S knows that Φ⌝, and that only moderate invariantism can successfully explain why speakers have all of these intuitions. In §7 I conclude that moderate invariantism correctly describes of the semantics of knowledge attributions, or at least does so better than its main current rivals.