The present disclosure relates to a separator for a lithium secondary battery, and a lithium secondary battery including same, the separator including: a porous substrate, and a heat-resistant layer on at least one surface of the porous substrate, wherein the heat-resistant layer includes a first coating layer including alumina, and a second coating layer including magnesium hydroxide, and the first coating layer and the second coating layer are consecutively disposed in a stacked form on the porous substrate.