A device and a method of unlocking a device are provided. The method of unlocking a device includes: determining whether an input tool of the device is separated from the device, when a disabled screen of the device is enabled; selecting one user interface from among a plurality of user inter faces for unlocking the device on the enabled screen of the device, based on the determination result; displaying the selected user interface on the screen of the device; and receiving a touch input with respect to the displayed user interface. The plurality of user interface include a user interface for receiving a touch input by the input tool and a user interface for receiving a touch input by a body part of a user