The catalytic dehydration of methyl alpha-hydroxyisobutyrate over various zeolites in a flow reactor is described. Both NaY and NaX are effective catalysts for the selective conversion of MOB to methyl methacrylate. Modification with K+ and Cs+ enhances the activity and selectivity of NaY but renders NaX a less effective catalyst. Acidic zeolites (HY, Beta, GdNaX, SmNaY, fluorinated SmNaY) were shown to be quite active but poorly selective with catalyst deactivation resulting from coke formation.