The environmental problems caused by the excessive usage of fossil fuel, prompted the need for an alternative source of energy. Renewable energy from biodiesel is one of the most promising substitutions of fossil fuel due its environmental-friendliness. In the present work NaOH-modified γ-alumina heterogeneous base catalysts were prepared using wet impregnation method, and characterized by Nitrogen Adsorption Analysis (BET), Fourier Transform Infra-Red (FTIR), X-Ray Powder Diffraction (XRD), basic back titration, and Temperature Programmed Desorption-CO2 (CO2-TPD). The catalysts were tested for the transesterification of rice bran oil with methanol, and the biodiesel product characterized by Fourier Transform Infra-Red-Attenuated Total Reflection (FTIR-ATR) and Nuclear Magnetic Resonance Spectroscopy (NMR) analyses. Catalyst synthesize with 50% NaOH was found to have the highest basic sites and when applied for the transesterification of rice bran oil it gave the highest yield of 81.2%. The high catalytic activity is attributed to the formation of NaAlO2 that is believed to contribute to the basicity of the catalyst.