The antisaccade (AS) task, which requires the ability to suppress unwanted reflexive glances, has proven to be a powerful tool for the analysis of executive control. Performing this task activates a large frontoparietal network, but which area is specifically responsible for reflexive saccade (RS) inhibition has not yet been demonstrated. We reversibly inactivated portions of the principal sulcus in 2 monkeys trained to perform AS and RS tasks. Here we show that inactivation of a circumscribed area in the ventral bank of the principal sulcus induced a strong impairment of RS inhibition without affecting RS triggering. Our results are compatible with a partitioning of the principal sulcus into functional subregions, in which a well-delineated area is critically involved in RS suppression.