A method is provided for measuring the wall thickness of transparent articles using uniform diverging light in the form of a small point source or elongated narrow line of light, measuring the spacial separation of the reflections from the nearest and furthest surface by means of a two-dimensional image sensor and a computational device to calculate the geometrical corrections needed to provide accurate thickness measurements. In situations where significant thickness variations occur, a symmetrical two view embodiment using two uniform diverging light sources and two image sensors at equal but opposite angles of incidence from the same side of the object, provides a means to correct for errors caused by internal prism effects as a result of undulations of either the nearest or furthest surface. This system provides accurate thickness measurements over a wide range of object movement.