A sprocket includes teeth defined relative to respective tooth centers spaced evenly about an axis of rotation. An inverted tooth chain includes rows of links each structured for inside flank engagement with the sprocket, with leading inside flanks of each row projecting outwardly relative to the trailing outside flanks of a preceding row. The leading inside flanks of each row are positioned to make initial meshing contact with an engaging flank of one of the sprocket teeth. At least some of the teeth are standard teeth and other ones of the teeth are flank-relieved teeth. The engaging flanks of the flank-relieved teeth are negatively offset as compared to the engaging flanks of the standard teeth measured relative to their respective tooth centers. The root surfaces leading the flank-relieved teeth are raised relative to the root surfaces leading the standard teeth.