The polymerization of methyl methacrylate was studied using Mn(acac)3, Co(acac)3, and Fe(acac)3complexes. The rate of polymerization at various complex and monomer concentrations were investigated and it was observed that the plots of Rpversus [M]2and Rpversus 1/[complex] were linear. The reactions were studied at different temperatures and the overall activation energies were computed to be 4.70, 5.50, and 6.40 kcal/mol for Mn3+, Co3+, and Fe3+complexes, respectively. The effect of inhibitor on the polymerization rate was studied. Using the well-known Tüdös equation, the Tüdös inhibitor constant was computed to be 10. A suitable kinetic scheme for the polymerization has been pictured.