To clarify the chemical compatibility between vanadium alloys and SiC, the extent of reactions, the products, and the structures of reaction layers in V/SiC, V-15Cr/SiC, and V-15Ti/SiC diffusion couples were studied at temperatures ranging from 1173 to 1523 K in an argon gas stream. The interfacial reactions were mainly dominated by the diffusion of carbon into the metal and alloys leading to the formation of the carbides which are of VC and V2C in the V/SiC and V-Cr/SiC systems and V2C and TiC in the V-Ti/SiC system. The remarkable internal carbides of V2C in the V-Cr alloy and TiC in the V-Ti alloy were also formed. The silicides of V5Si3 and V3Si which were presumably formed by the diffusion of vanadium into SiC side were present in the SiC side of the original interface of SiC and V-metal or alloys. The growth of the reaction layer in each system followed a parabolic rate law. The compatibility between the vanadium alloys and SiC from the standpoint of the growth kinetics of the reaction layer was superior to other metals such as iron and nickel. Furthermore, these reactions were used as a surface treatment in order to improve oxidation resistance of the vanadium alloys. The effect of the surface treatment was especially beneficial for the V-Ti alloy.