Techniques are disclosed relating to credential sharing for user authentication. In some embodiments, a first computing device maintains a credential manager that stores a plurality of user credentials usable to authenticate a user. The first computing device receives a request from the user to send one of the plurality of user credentials to a second computing device. In response to the request, the first computing device sends the user credential to the second computing device. The second computing device is configured to determine whether an application of the second computing device is presenting an authentication prompt to a user and, in response to determining that the authentication prompt is being presented, populate one or more fields of the authentication prompt with the user credential. In some embodiments, the second computing device is configured to store the user credential in a credential manager maintained by the second computing device.