We systematize the well-known electrolytes for the high-temperature electrochemical synthesis of borides, carbides, and silicides of metals of the IV–VIA groups by the classes of synthesized compounds. We also generalize the conditions of their deposition from electrolytes of different compositions and analyze the results of recent investigations in this field. Hypotheses on the possible mechanisms of synthesis processes are advanced. Furthermore, we prove the possibility of electrochemical synthesis of borides and silicides of metals of the IV group and carbides of metals of the VI group in the thermodynamic mode as well as that of carbides of metals of the V group and borides and silicides of metals of the VI group in the kinetic mode. We demonstrate the possibility of using carbon dioxide or carbonates of alkali metals as a source of carbon in the synthesis of metal carbides. It is established that the composition of synthesized powders is determined by the concentrations of components in the electrolyte, temperature, cathodic current density, and the duration of electrolysis. We show the possibility of synthesis of three-component hard-alloy carbide compositions. Finally, we determine the technological parameters of production of single-phase powders.