Disclosed is a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same. The non-aqueous electrolyte including an ionizable lithium salt and an organic solvent may further include (a) 1 to 10 parts by weight of a compound having a vinylene group or vinyl group per 100 parts by weight of the non-aqueous electrolyte, and (b) 10 to 300 parts by weight of a dinitrile compound having an ether bond per 100 parts by weight of the compound having the vinylene group or vinyl group. The lithium secondary battery comprising the non-aqueous electrolyte may effectively suppress the swelling and improve the charge/discharge cycle life.