Techniques are disclosed relating to sharing a user credential between computing devices. In some embodiments, a first computing device stores a set of user credentials usable to authenticate a user and receives, from a second computing device, a request for a user credential to be provided responsive to an authentication prompt associated with the second computing device. In such an embodiment, the request includes an indication of a service for which the authentication prompt is being presented. Based on the indication, the first computing device determines whether the stored set of user credentials includes a user credential relevant to the authentication prompt and presents a selection prompt asking a user of the first computing device to select a one of the stored set of user credentials to provide to the second computing device for authentication to the service, the relevant user credential being identified in the selection prompt.