A flat-fold, filtering, face-piece respirator 10 that has a harness 14, a mask body 12, and first and second flanges 30a, 30b. The mask body 12 is capable of being folded flat for storage and can be opened into a cup-shaped configuration for use. The mask body 12 comprises a filtering structure 16 and has the first and second flanges 30a, 30b disposed on first and second mask body sides. The first and second flanges 30a, 30b project both laterally x and frontally y from the mask body 12. The provision of the flanges on each side of the respirator is beneficial to ease of mask donning, doffing, and adjustment, and to face fit and maintaining the open shape or configuration of the mask body.