An apparatus and method for providing an adaptive on-screen keyboard are provided. The apparatus includes a sensor for detecting touch action of a user from a touch screen, a pattern recognizer for recognizing a touch pattern of the user using the detected touch action of the user, a rearrangement processor for reconstructing the key arrangement of the on-screen keyboard to be provided through the touch screen on the basis of the recognized touch pattern of the user, and a display for displaying the on-screen keyboard on the basis of information on the reconstructed key arrangement. Thus, the apparatus can increase the convenience of use when the user makes use of the on-screen keyboard.