Partially hydrolyzed orthosilicates, primarily tetraethoxysilane (TEOS), are used as binders in zinc-rich coatings. One possible source of TEOS is tetramethoxysilane (TMOS) which is prepared from elemental silicon and methanol. The TEOS is prepared when TMOS is reacted with ethanol in the presence of an acid catalyst. Research involving kinetic and mechanistic information of this acid-catalyzed alcoholysis is somewhat limited. In this study we have investigated the rate of the reaction using several different catalysts. We have determined the order of the reaction and its activation energy, from which we have proposed a mechanism. This knowledge will be helpful in the preparation of zinc-rich coatings.