Provided are an apparatus and method for providing security in a wireless communication system. A user equipment (UE) may transmit a registration request message to an access and mobility management function (AMF), in response to reception of a registration reject message from the AMF, transmit an attach request to a mobility management entity (MME), and receive an attach accept from the MME, wherein, when the AMF and the UE have a security context, a security-protected registration reject message may be transmitted by the AMF to the UE, a registration request from the UE may be redirected from the AMF to the MME, and when at least one of the AMF and the UE does not have security context information, the attach request may include security verification information.