Concepts and technologies disclosed herein are directed to single packet authorization (“SPA”) in a cloud computing environment. A compute node can include a virtual switch operating on at least a portion of a plurality of hardware resources of a cloud computing environment, a virtual firewall, a cloud workload executing a cloud service, and a SPA service. The virtual switch can receive a SPA request from a SPA client executing on a computing device. The virtual switch can forward the SPA request to the virtual firewall and to the SPA service. The virtual firewall can deny the SPA request in accordance with a firewall policy. The SPA service can utilize a SPA validation scheme to validate the SPA request. The virtual firewall can implement a temporary firewall policy to allow incoming packets from the SPA client and directed to the cloud service.