The negative effects of sleep loss on sleepiness, performance, and mood have been well-documented. Less is known, however, about possible negative effects of sleep extension and findings are inconsistent. This study investigated the Rip Van Winkle effect, comparing the effects of a single night of sleep extension (11 h time-in-bed, TIB) to control sleep (8.5 h TIB) following three nights on a nominal (8.5 h TIB) or restricted (6.5 h TIB) sleep schedule. Nine healthy males (mean age 21 y; mean habitual sleep 7.9 h) participated in a four-way cross-over design. Participants completed sleepiness and mood scales, a range of performance tasks, and multiple sleep latency tests approximately every two hours following in-laboratory baseline and experimental nights. Objective sleepiness was reduced (i.e., sleep onset latency was delayed) following sleep extension under both nominal and restricted baseline conditions. Self-reported mood was modestly improved following sleep extension. No changes in subjective sleepiness or objectively measured performance were observed across conditions. The results indicate that one night of sleep extension, following either nominal or restricted sleep, can reduce objective sleepiness but does not appear to consistently alter performance or subjective sleepiness.