Currently, there is a great deal of research activity on the incorporation of magnetic ions into semiconductors to produce ferromagnetism. These diluted magnetic semiconductors (DMSs) are of interest both to theorists, because of their unusual mechanisms of magnetic behavior, and to experimentalists, because the manipulation of spin in addition to charge promises devices based on spin polarized transport. The most extensively studied DMS systems to date are based on II-VI and III-V semiconductors doped with manganese. Recently, we discovered a new class of diluted magnetic semiconductors that differ from the traditional compounds in a number of intriguing ways. The narrow band gap tetradymite-type semiconductors with the form A2VB3VI (A = Sb, Bi and B = Se, Te) are normally associated with thermoelectric cooling devices. However, both Sb2-xVxTe3 and Bi2-xFexTe3 display ferromagnetic semiconductor behavior. In this talk, I will discuss the interesting properties of these compounds as well the doping of other 3d transition metals in the tetradymite structure semiconductors.