Provided are a separator for a lithium secondary battery and a lithium secondary battery comprising the same. The separator for a lithium secondary battery includes: a porous substrate; and a coating layer disposed on one side or both sides of the porous substrate and including a first inorganic particle and a second inorganic particle having different lengths of a major axis, and a binder, wherein a moisture content is less than 800 ppm after being left for 12 hours at a temperature of 40° C. and relative humidity of 90%.