Abstract: A computer-implemented method for authenticating users may include (i) identifying, on a computing system, an attempt by a user to access an application that requires authentication, (ii) sending, in response to identifying the attempt to access the application, a request for an authentication token for the application to a third-party platform for which the user has a pre-existing user account and to which the user is currently authenticated on the computing system, (iii) receiving the authentication token for the application from the third-party platform that is associated with the pre-existing user account for the user in response to sending the request for the authentication token, and (iv) authenticating the user to the application on the computing system via the authentication token associated with the pre-existing user account in response to receiving the authentication token. Various other methods, systems, and computer-readable media are also disclosed.