Traditional accounts of the conditions on communicative success are invariantist. For example, some authors claim that, for communication to succeed, a hearer must always grasp the very content that the speaker expressed with her utterance; others claim that success is always proportional to the degree to which the hearer understands this content. In this paper, I argue that these invariantist approaches cannot offer a comprehensive account of communicative success. When we attempt to communicate, it is usually with the intention to secure some perlocutionary effect beyond the communicative exchange itself (for example, to get our interlocutor to pass the salt, or to convince her to form a particular belief). I argue that, relative to these intentions, it may not matter whether a hearer perfectly understands the speaker; it may not even matter if the hearer’s understanding is quite poor overall. In place of invariantist conditions (or perhaps, in addition), I propose an approach that is context-dependent in the following sense: holding fixed the content expressed by the speaker, differences in features of the broad context of the speech exchange can determine differences in the standards for communicative success. On this approach, success requires that the hearer understand the content expressed by the speaker in ways that are relevant to the speaker’s perlocutionary intentions.