Highly textured strontium barium niobate thin films were depositedinsituby low pressure metalorganic chemical vapor deposition. [001]‐oriented strontium barium niobate films on single crystal (100) magnesium oxide substrates were obtained at a growth temperature of 800 °C. Second‐harmonic generation of 1.064 &mgr;m incident light was measured on the thin films. The nonlinear optical susceptibility of the films was as high as 8.7 times that of quartz (∼3.0 pm/V), which is comparable to the bulk value. ©1995 American Institute of Physics.