Solar thermoelectric generators (STEGs) are two steps energy harvesting systems that convert solar power into electricity. Even if the first generation of this kind of systems was developed in the first half of the twentieth century the interest around this technology has been intermittent. Only in recent years the progress of the thermoelectric material efficiency stimulated a renewed interest on STEGs as a viable alternative to harness solar energy. In this paper the basic aspects of STEG technology, along with the analysis of its efficiency, and the state of the art of this field are discussed.