An information processing system includes a receiving unit that receives user identification information and organization identification information from an external device, and an authentication unit that performs authentication of the user identification information and the organization identification information received by the receiving unit using a first storage unit storing one or more sets of user identification information in association with organization identification information. When the authentication unit receives a federated authentication request to access an external service from the external device that is authenticated, the authentication unit sends a federated authentication response to the external device if the organization identification information received from the external device and the external service designated in the federated authentication request are associated with each other in a second storage unit storing the organization identification information in association with information on one or more external services that have established a trust relationship for authentication.