The greater effectiveness of peripheral over central masks was investigated in an experiment with 16 separate target-mask displays: a single mask letter above, to the left of, below, or to the right of a single target letter, and the pair of letters above, to the left of, below, and to the right of fixation. Close target-mask spacing was used, and the center points of the target-mask pairs were held constant. Peripheral masking was more effective than foveal masking in both the vertical and horizontal directions. Furthermore, masks on the same radius as the target (whether peripheral or central) were more effective than masks off that radius. The results were consistent with Wolford’s (1975) feature-perturbation model of visual masking.