Discussed is a separator for a lithium secondary battery and a lithium secondary battery including the same, more specifically, a separator for a lithium secondary battery including a porous substrate and a coating layer on at least one surface of the porous substrate, wherein the coating layer includes a defect-containing molybdenum disulfide. The separator for lithium secondary battery adsorbs lithium polysulfide through the coating layer comprising the defect-containing molybdenum disulfide and suppresses the growth of a lithium dendrite, thereby improving the capacity and lifetime characteristics of the lithium secondary battery.