Testimony is responsible, either directly or indirectly, for much of what we know, not only about the world around us but also about who we are. Despite its relative historical neglect, recent work in epistemology has seen a growing recognition of the importance and scope of testimonial knowledge. Most of this work has focused on two central questions, which will be the main topics of this article. First, is testimonial knowledge necessarily acquired through transmission from speaker to hearer, or can testimony generate epistemic features in its own right? Second, is justified dependence on testimony fundamentally basic, or is it ultimately reducible to other epistemic sources, such as perception, memory, and reason? Testimony itself is typically understood quite broadly so as to include a variety of acts of communication that are intended or taken to convey information—such as statements, nods, pointings, and so on. (For a full development of this view, see Lackey 2008.) Knowledge that is distinctively testimonial requires belief that is based or grounded in, not merely caused by, an instance of testimony. For instance, suppose that I sing “I have a soprano voice” in a soprano voice and you come to believe this entirely on the basis of hearing my soprano voice. (This is a variation of an example found in Audi 1997.) While my testimony is certainly causally relevant to the formation of your belief, the resulting knowledge is based on your hearing my soprano voice rather than on what I testified to, thereby rendering it perceptual in nature. What is of import for distinctively testimonial knowledge is that a given belief be formed on the basis of the content of a speaker’s testimony. This prevents beliefs that are formed entirely on the basis of features about a speaker’s testimony from qualifying as instances of testimonial knowledge.