The present invention relates to a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same, and particularly, to a non-aqueous electrolyte solution for a lithium secondary battery which includes an ionizable lithium salt, an organic solvent, and an additive, wherein the additive is a mixed additive which includes lithium difluorophosphate, tertiary alkylbenzene, and tetra-vinyl silane in a weight ratio of 1:1 to 4:0.05 to 0.5, and the additive is included in an amount of 2.5 wt % to 4.5 wt % based on a total weight of the non-aqueous electrolyte solution for a lithium secondary battery, and a lithium secondary battery including the same.