The reactions of acetic acid have been investigated on the (111) surface of uranium dioxide single crystals, which was characterized by low energy electron diffraction and Auger electron spectroscopy. Temperature programmed desorption (TPD) of this molecule displays a rich chemistry on both the stoichiometric and electron beam sputtered surfaces. Acetic acid-TPD on a stoichiometric surface yields ketene (dehydration) as the main product, plus acetaldehyde as the minor product. On an electron beam sputtered surface, two additional association products were observed-butene and crotonaldehyde. The carbon yield of ketene on the stoichiometric surface was comparable to that of CeO2(111) and TiO2(001), higher than that of ZnO(0001) and Cu2O(100), but lower than that of MgO(100). This investigation has shown the ability of UO2(111) surfaces to dehydrate, reduce, and reductively couple organic molecules.