Over the last 2 centuries, the predominant view of the cerebellum has been that it is part of a motor control system. Evidence is now presented that the neocerebellum, the evolutionarily newest region of the cerebellum, may also be involved in a key mental operation: the voluntary shift of selective attention between sensory modalities. It is theorized that this newly recognized function may operate via previously described sensory modulation properties of the cerebellum and its many connections with areas known to be important for selective attention, such as the pulvinar, the superior colliculus, and the parietal and frontal cortices.