The growth behavior of diamond films synthesized from halomethane reactants is studied in a hot‐filament chemical vapor deposition reactor. The growth characteristics of methane and several chloromethane reactants (CH2Cl2, CHCl3, and CCl4) are examined over a number of reactant concentrations, substrate temperatures (700–900 °C), reactor pressures, and filament temperatures. The results indicate that in comparison to methane, chloromethane reactants generally yield higher rates of diamond film growth, with this difference becoming more pronounced at lower substrate temperatures. As a result, chloromethane reactants possess potential in facilitating diamond growth at low growth temperatures. Possible explanations for this behavior involving gas phase and surface reaction mechanisms of chloromethane reactants are proposed.