There is disclosed a process for producing methyl methacrylate through gas-phase catalytic reaction of methyl .alpha.-hydroxyisobutyrate which comprises feeding methanol in an amount by weight of 0.1 to 3.0 times the methyl .alpha.-hydroxyisobutyrate in a reactor along therewith and proceeding with the reaction at a reaction temperature in the range of 230.degree. to 300.degree. C. by the use of a transition-type synthetic faujasite zeolite having a specific lattice constant and a specific Na content (Na/Al) as the catalyst. The process is capable of stably producing the objective product having excellent quality in high yield for a long period of time while preventing the problems of early deterioration of the catalyst and coloring of reaction product.