The automatic selection of an identity provider to be used to authenticate users when requesting to access network resources for a tenant. The authentication is initiated by checking the username against the directory of the tenant. If that check results in finding an entry for the username in that directory, the entry is checked for an identity provider. If that check results in finding an identity provider, the user is directed to that found identity provider for authentication. Thus, in many, most, or all cases, an identity provider is found and selected for authentication of the user without the user having to manually select the identity provider. The username may be an internal user of an entity. The selection of the identity provider works in either case since there would still be an entry for that user in the directory of the tenant.