Stereo correspondence smoothness tool techniques are described. In one or more implementations, an indication is received of a user-defined region in at least one of a plurality of stereoscopic images of an image scene. Stereo correspondence is calculated of image data of the plurality of stereoscopic images of the image scene, the calculation performed based at least in part on the user-defined region as indicating a smoothness in disparities to be calculated for pixels in the user-defined region.