A stereoscopic image display device and method of removing jagging of a stereoscopic image. The method comprises: detecting left edges and right edges by analyzing left-eye image data and right-eye image data; detecting a row line as a complicated line if a number of the left edges or the right edges in the row line is equal to or more than a complicated line threshold value, and counting a number of complicated lines; generating a complexity signal having a first logic level if the number of the complicated lines is equal to or more than a complexity detection threshold value; and generating the complexity signal having a second logic level if the number of the complicated lines is less than the complexity detection threshold value.