A stereoscopic image display is discussed. The stereoscopic image display includes a display panel including data lines, gate lines crossing the data lines, thin film transistors (TFTs) that are turned on in response to gate pulses from the gate lines, and a plurality of pixels, a data driving circuit that converts digital video data into a data voltage and supplies the data voltage to the data lines, a gate driving circuit sequentially supplying the gate pulses synchronized with the data voltage to the gate lines, and a timing controller that receives a timing signal, 2D image data, and 3D image data from an external host system, supplies the digital video data to the data driving circuit, and controls an operation timing of the data driving circuit and an operation timing of the gate driving circuit.