Since the determination of the first crystal structure of a glutamate transporter homolog Glt_Ph 16 years ago, the structural biology of glutamate transporter has progressed remarkably. To understand the complicated transport cycle of ion-coupled glutamate transport, each state’s high-resolution structural information in the transport cycle is essential. Many of the structural information and insights about the sodium-coupled symport mechanism were gained from structural studies of prokaryotic homologs sodium-aspartate symporters, Glt_Ph and Glt_Tk. Moreover, further insights were gained from recently unveiled structures of mammalian glutamate transporters (EAATs). Here we review Glt_Ph, Glt_Tk, and mammalian glutamate transporters’ structures and discuss how they help us to understand the ion-coupled transport mechanism in glutamate transporters.