Methods and apparatus to calibrate and/or validate stereoscopic depth sensing systems are disclosed. An example apparatus includes an image generator to generate a first image for a first image sensor; and generate a second image for a second image sensor. First content in the first image is to be shifted relative to corresponding second content in the second image by a shift amount. The shift amount based on a target depth to be tested. The example apparatus further includes a calibration controller to cause the first and second images to be presented on the display screen; and calibrate the first and second image sensors based on a difference between the target depth and a measured depth. The measured depth based on an analysis of the first and second images as captured by the first and second image sensors when the first and second images are presented on the display screen.