We have developed a method for measuring the thickness of thin films that is nondestructive, noncontact and that can make measurements with 2‐&mgr;m spatial resolution (i.e., 2‐&mgr;m spot size) on both optically opaque as well as optically transparent films. With this method, which is based on the use of high‐frequency thermal waves, thicknesses of Al and SiO2films on Si substrates have been measured in the 500–25 000‐A˚ range.