There is provided a vehicle lower portion structure including: a pillar inner panel; a pillar outer panel having a hat-shaped cross-section, and at whose vehicle front-side end portion and vehicle rear-side end portion are formed outer flange portions that are joined to the inner flange portions; a first ridge portion that extends in a vehicle up-down direction at a front wall of the pillar outer panel and at an end portion on the outer side in the vehicle width direction within an area facing a front wheel in a vehicle front-rear direction; and a second ridge portion that extends in the vehicle up-down direction on the inner side in the vehicle width direction of the first ridge portion within the area, and so as to protrude towards the vehicle front side beyond the first ridge portion when viewed in a cross-sectional plan view.