An experimental investigation into the ultimate bearing capacity of ring foundations supported by a sand bed with and without geogrid reinforcement is reported. The parameters investigated are optimum ring width, the effect of depth of first reinforcement, the number of reinforcement layers, and the effect of reinforcement layer length on the ultimate bearing capacity of ring foundations. The results of the experimental study proved that the reinforcement had a considerable effect on the ultimate bearing capacity of the ring foundations. It was also proved that ultimate bearing capacity values can, depending on the reinforcement geogrid arrangement, be improved by up to three times that of the unreinforced case. It was shown that a ring foundation with the optimum width showed similar performance to that of full circular foundation with the same outer diameter on the ring foundations for both the unreinforced and reinforced cases.