Remembering to execute deferred goals (prospective memory) is a ubiquitous memory challenge, and one that is often not successfully accomplished. Could sleeping after goal encoding promote later execution? We evaluated this possibility by instructing participants to execute a prospective memory goal after a short delay (20 min), a 12-hr wake delay, or a 12-hr sleep delay. Goal execution declined after the 12-hr wake delay relative to the short delay. In contrast, goal execution was relatively preserved after the 12-hr sleep delay relative to the short delay. The sleep-enhanced goal execution was not accompanied by a decline in performance of an ongoing task in which the prospective memory goal was embedded, which suggests that the effect was not a consequence of attentional resources being reallocated from the ongoing task to the prospective memory goal. Our results suggest that consolidation processes active during sleep increase the probability that a goal will be spontaneously retrieved and executed.