A run-flat radial tire has a tire section height SH equal to or greater than 115 mm and is equipped with a side-reinforcing rubber layer extending along an inner surface of a carcass from one tire side portion to another tire side portion wherein a tire equatorial plane CL is sandwiched in between the one tire side portion and the another tire side portion, wherein a thickness GE of the side-reinforcing rubber layer at the position of the tire equatorial plane and a thickness GA of the side-reinforcing rubber layer at positions where the carcass reaches its maximum width satisfy the relational expression GE0.6GA.