This article considers the teaching role of reference librarians by studying the teachable moment in reference transactions, and users’ response to that instruction. An empirical study of instruction was conducted in both virtual and traditional reference milieus, examining the following three services: IM (Instant Messaging), chat, and face-to-face reference. The authors used the same criteria in separate studies of all three services to determine if librarians provided analogous levels of instruction and what factors influenced the likelihood of instruction. Methodology employed included transcript analysis, observation, and patron surveys. Findings indicated that patrons wanted instruction in their reference transactions, regardless of medium, and that librarians provided it. However, instructional techniques used by librarians in virtual reference differ somewhat from those used at the reference desk. The authors conclude that reference transactions, in any medium, represent the patron’s point-of-need, thereby presenting the ideal teachable moment.