Technologies for depth-based user authentication include a mobile computing device to display a login image including a depth channel on a display of the mobile computing device. The mobile computing device determines a selection of a plurality of objects of the login image made by a user of the mobile computing device, generates a user-selected password based on a relative depth of each object of the plurality of objects selected by the user, and permits access to the mobile computing device in response to a determination that the user-selected password matches a device login password.