Critics contend that Aristotelianism demands too much of the virtuous person in the way of knowledge to be credible. This general charge is usually directed against either of two of Aristotelianism’s apparent claims about the necessary conditions for the possession of a single virtue, namely that 1) one must know what all the other virtues require, and 2) one must also be the master of a preternatural range of technical/empirical knowledge. I argue that Aristotelianism does indeed have a very high standard when it comes to the knowledge necessary for the full possession of a virtue, in both of these respects. However, focus on the necessary conditions for full virtue tends to obscure an important fact: some kinds of knowledge are much more important to various virtues than others are. A proper appreciation of the significance of this fact will go a long way toward answering critics’ worries about Aristotelianism’s knowledge requirements.