n-Butenes have been oligomerized at temperatures lower than 450 K in the liquid phase over H-mordenite in a continuously stirred tank reactor. The composition and molecular weight of the products are very dependent on reaction temperature. Products are essentially dimers, trimers, and tetramers. The complex reactions were modeled by taking into account only the type of carbonium ion; the initial rates showed that the oligomerization reactions followed a Rideal mechanism. The dimerization rate constants of butenes and oligomers decrease with increasing number of carbon atoms of the olefins, while the adsorption constants increase with the hydrocarbon chain length. A model for the conversion of butenes to liquid products over H-mordenite is proposed. This model fits the experimental data rather well, although some simplifying approximations were made to describe these complex reactions.