A detailed mechanistic study of the hydrosilylation of benzaldehyde catalyzed by MoO2Cl2 is reported. On the basis of DFT calculations (B3LYP/6-311++G**), a reaction pathway via initial silane activation is proposed. SiH and CH activation energies by other metal-oxo compounds like RuO4, OsO4, and MnO4- are compared to MoO2Cl2. MO4-type metal-oxo compounds follow a different mechanism, forming highly exergonic intermediates, which prevent a catalytic reaction, whereas MoO2Cl2 prefers a reaction pathway via thermoneutral intermediates.