Provided are a separator, a method of manufacturing the separator, and an electrochemical device including the separator. According to an embodiment of the present disclosure, a separator including a porous substrate and an inorganic particle layer provided on at least one surface of the porous substrate, the inorganic particle layer including inorganic particles, a hydrolytic condensate binder of a polar silane compound, and an aqueous polymer binder, wherein an amount of change in peel strength, ΔP is 1.1 or more may be provided.