An electrolyte solution for a lithium secondary battery and a lithium secondary battery including the electrolyte solution are provided. The electrolyte solution includes an additive represented by Chemical Formula 1, an organic solvent and a lithium salt:




wherein in Chemical Formula 1, R1 and R2 are each independently hydrogen or a substituted or unsubstituted C1-C5 alkyl group, X is O or S, and L is a substituted or unsubstituted C1-C5 alkylene group. The lithium secondary battery including the electrolyte solution provides enhanced high-temperature properties.