Alkoxylation, hydrosilylative‐alkoxylation, and dehydrogenative‐polymerization are some of the most widely used transformations in synthetic chemistry. However, these transformations are traditionally catalyzed by precious, and rare late‐transition metals. Presented here is a molecularly defined iron complex that catalyzes alkoxylation, tandem hydrosilylative‐alkoxylation, and dehydrogenative polymerization of silanes under mild conditions. The iron complex [Fe(CO)₄(H)(SiPh₃)] 1 catalyzes a direct Si−O coupling reaction between an array of silanes and alcohols to produce desired alkoxysilanes in excellent yield, with H₂ as the only byproduct. The iron catalyst tolerates various functional groups and provides access to 20 alkoxysilanes, including essential molecules such as β‐citronellol and cholesterol. Further, complex 1 catalyzes the polymerization of renewable diol and silane monomer to produce a renewable and degradable poly(isosorbide−silyl ether). Remarkably, complex 1 catalyzes a tandem hydrosilylative‐alkoxylation of alkynes under mild conditions to yield unsaturated silyl ethers. The synthetic utility has been demonstrated by gram‐scale alkoxylation and hydrosilylative‐alkoxylation reactions.