Provided is a run flat tire comprising a side reinforcing layer on a sidewall part, wherein a rubber composition of the side reinforcing layer has a complex elastic modulus at 100° C. (E*100) of 5.0 to 17 MPa and a loss tangent at 60° C. (60° C. tan δ) of 0.020 to 0.100 MPa, and wherein, where a tire cross-sectional width is defined as Wt (mm) and a tire outer diameter is defined as Dt (mm), Wt and Dt satisfy any of the following inequality (1), (2), and (3): Wt