This chapter describes the mechanisms through which the experience of processing ease, or fluency, can influence attitudes and persuasion. In particular, we argue that ease can impact attitude change not only by serving as a peripheral cue (e.g., being experienced as positive affect or as input to an availability heuristic), but also by affecting the thoughts people generate and the confidence with which those thoughts are held. Of importance, the conditions necessary for each of these processes to operate are specified in this review. Because the different mechanisms operate in different contexts, appreciation of the multiple roles for ease can shed new light on situations in which ease effects should be more or less likely to emerge, and more or less likely to persist.