The present invention refers to a sole structure for sports footwear comprising a stiffening element (9) and an outsole formed by one or more portions (12, 13) suitable to hold, preferably in a removable manner, the stiffening element (9); the sole structure (1) also includes a midsole (2) provided with a plurality of centering elements (3) projecting from the midsole (2), and the stiffening element (9) is provided with a plurality of openings (10) corresponding and countershaped to the plurality of centering elements (3), so that the plurality of openings (10) matingly cooperates with the plurality of centering elements (3) to prevent a relative movement between the stiffening element (9) and the midsole (2) on a plane defined by the midsole (2).