The authors explore the well-documented tendency for people to predict that they will finish tasks earlier than they actually do. Whereas previous research has tied this optimistic bias to the operation of specific cognitive processes, the present studies examine the interplay between motivation and cognition. Two studies supported the hypothesis that incentives to finish tasks quickly exacerbate the optimistic bias. An initial field study using a naturally occurring incentive manipulation demonstrated that individuals who expected an income tax refund were more (overly) optimistic in predicting when they would complete their income tax forms than those who did not expect a refund. A laboratory experiment using a word generation task replicated this general effect and identified mediating cognitive mechanisms: Monetary incentives for early completion led to optimistic predictions, increased attention to detailed future plans, and reduced attention to relevant past experiences.