An electrolyte for a lithium secondary battery and a lithium secondary battery including the electrolyte are provided. The electrolyte for a lithium secondary battery may include a lithium salt, an organic solvent, and an additive represented by Formula 1, where at least one selected from among R1 to R6 may be a C1-C5 alkyl group including a cyano group, and one or two selected from among R1 to R6 may each be a fluorinated C1-C5 alkyl group.