The aim of this pilot study was to quantify the impact of sleep deprivation on psychophysiological reactivity to emotional stimuli. Following an adaptation night of sleep in the lab, healthy young adults were randomly assigned to either one night of total sleep deprivation or to a normal sleep control condition. The next afternoon, responses to positive, negative, and neutral picture stimuli were examined with pupillography, an indicator of cognitive and affective information processing. Only the sleep-deprived group displayed significantly larger pupil diameter while viewing negative pictures compared to positive or neutral pictures. The sleep-deprived group also showed anticipatory pupillary reactivity during blocks of negative pictures. These data suggest that sleep deprivation is associated with increased reactions to negative emotional information. Such responses may have important implications for psychiatric disorders, which may be triggered or characterized by sleep disturbances.