The mechanical and electronic properties of M23C6- (M = Fe, Cr, Mn) and M23C6-type multicomponent carbides are investigated systematically by first-principles calculations. The values of cohesive energy and formation enthalpy exhibited thermodynamically stable structures of these carbides. The stress–strain method and Voigt-Reuss-Hill approximation were used to calculate the elastic constants and moduli, respectively. The mechanical properties of the doped Fe or Mo in M23C6 compounds are superior to the pure phases of Cr23C6, Mn23C6 and Fe23C6. Mechanical anisotropy of these compounds was illustrated from the anisotropic index and different shapes of the surface contour by Young's modulus. Moreover, the total density of states of M23C6 compounds indicated that the bonding behaviors of M23C6 compounds were combinations of metallic and covalent bonds.