MBS key distribution includes processing group information associated with an MB session context received from an AF. At least a portion of the group information comprises a TMGI. A plurality of session join requests received from a plurality of UEs are processed. Each of the plurality of session join requests include the TMGE and are associated with the MB session context. A request associated with the MB session context for transmission to an MB-SMF is encoded. A response associated with the MB session context received from the MB-SMF is processed. The response includes a key derived for each of a portion of the plurality of UEs using a UE ID and the TMGI. A DL NAS message and an N2 message are encoded for the plurality of UEs and a base station, respectively. The DL NAS message and the N2 message include the derived key.