A run flat tire with reinforced sides, wherein inner and outer rubber thickness ratios centered on a carcass layer in a side wall portion are stipulated and a side filler extending in the tire radial direction is embedded on the outer wall surface side of the side wall portion. In this run flat tire, the modulus of the side filler/modulus of a side reinforcing layer, the modulus of a rim cushion/a modulus of the side filler, the cross-sectional area of a bead filler/cross-sectional area of the side filler, the cross-sectional area of the side filler/cross-sectional area of the side reinforcing layer, the rubber hardness of the side reinforcing layer, and the material of belt cover layers are each stipulated.