Concepts and technologies disclosed herein are directed to session continuity between software-defined network (“SDN”) controlled and non-SDN controlled wireless networks. In one embodiment, an SDN controller can determine that a handover of a user equipment (“UE”) from a base station operating under control of the SDN-controlled network to a further base station operating under control of a non-SDN-controlled network has occurred. The SDN controller can establish over an interface between the SDN controller and a packet gateway (“P-GW”), a tunnel through which to exchange handover data associated with the handover and a session IP address for a session in which the UE is involved. The SDN controller can provide, over the interface and through the tunnel, the handover data and the session IP address to the P-GW.