Graphite oxide (GO) is shown to be an efficient heterogeneous catalyst for the polymerization of various olefin monomers, including n-butyl vinyl ether, N-vinylcarbazole, styrene, and sodium 4-styrenesulfonate. The GO-catalyzed polymerization of n-butyl vinyl ether (0.1–5.0 wt% GO relative to monomer) proceeds rapidly under solvent-free conditions and affords polymers with moderate number average molecular weights and broad polydispersities. Analysis of the carbon recovered at the conclusion of the polymerization reactions reveals that the material's catalytic activity is retained and multiple polymerization cycles can be performed without regenerating the catalyst. GO also catalyzes the polymerization of N-vinylcarbazole and styrene, although only low molecular weight polymers are obtained. Sodium 4-styrenesulfonate polymerizes in the presence of GO to afford poly(sodium 4-styrenesulfonate) (PSS) composites. After thermal treatment, the composites can be fabricated into electrodes for use in electrochemical double layer capacitors (EDLCs). The devices display high specific capacitances (25–120 F g−1) and low equivalent series resistances (14–27 Ω).