Аннотация:Research carried out at the Shternberg Astronomical Institute on young star groups is reviewed. Particular consideration is given to the origin and structure of star clusters; star associations; star complexes; dispersed clusters and the distance scale; dispersed clusters and Cepheids; variable stars in young clusters and associations; and Cepheids in star complexes. A classification scheme for star groups is presented, which consists of clusters, associations, complexes, and superassociations.