This study aims to report the preliminary results of the transesterification of blended vegetable oil with ethanol to produce biodiesel using different mesoporous silica loaded with MgO as solid base catalysts. Variables that might affect the catalytic activities, such as the type of silica supports (MCM-41, KIT-6, and SBA-15), precursor salts (magnesium acetate and nitrate), and loading methods (impregnation and in situ coating), were investigated. Among all of the catalysts tested in this study, MgO-impregnated SBA-15 exhibits the highest activity for the production of biodiesel, achieving a conversion as high as 96% within 5 h. While the effect of the type of host material used is inconclusive in this study, the catalyst activity appears to be related to its surface Mg concentration, which varies with the loading method when the same host material is used. The effect of the type of precursor salt used for catalyst functionalization, however, was found to be unimportant.