A method for access network signaling protocol interworking for user authentication includes receiving, from a node in an access network, a message formatted according to a signaling protocol of the access network and containing an authentication payload formatted according to an authentication protocol. The method further includes, in response to receiving the message, formulating a message formatted according to a signaling protocol of a cellular network, the message including the authentication payload formatted according to the authentication protocol. The method further includes forwarding the message formatted according to the signaling protocol of the cellular network to a node in the cellular network that implements the authentication protocol, the message including the authentication payload formatted according to the authentication protocol.