We have demonstrated the feasibility of heteroepitaxial growth of Ga0.51In0.49P/GaAs layers on Si substrates by low‐pressure organometallic vapor phase deposition. The growth parameters of the GaAs buffer layer were confirmed to be the controlling factors in obtaining higher quality Ga0.51In0.49P on Si. Under the optimum growth conditions, specular single‐crystal Ga0.51In0.49P layers can be reproducibly obtained. The room‐temperature electron mobility of the undoped Ga0.51In0.49P epilayer can reach 1000 cm2/V s with a carrier concentration of 2×1016cm−3. The efficient photoluminescence indicates that the Ga0.51In0.49P grown layer is of high optical quality. In addition, the GaAs intermediate layer is also effective in reducing the residual tensile stress in the Ga0.51In0.49P film on Si. The results presented can compete with those reported previously for the OMVPE‐grown GaxIn1−xP on GaAs substrates.