Polycrystalline gadolinia-doped ceria (GDC) surfaces were studied using low-energy (5-400 eV) electron stimulated desorption (ESD). H+, O+, and H3O+ Were the primary cationic desorption products with HI as the dominant channel. H+, H3O+, and O+ have a 22 eV threshold followed by a yield change around 40 eV. HI also has an additional yield change similar to 75 eV and O+ has an additional change similar to 150 eV. The O+ ESD yield change similar to 150 eV may indicate bond breaking of Gd-O and the involvement of oxygen vacancies. The H+ and H3O+ threshold data collectively indicate the presence of hydroxyl groups and chemisorbed water molecules on the GDC surfaces. ESD temperature dependence measurements show that the interaction of water with GDC surface defect sites, mainly oxygen vacancies, influences the desorption of H+, O+, and H3O+. The temperature dependence of the O+ ESD at 400 eV incident electron energy yields a 0.21 eV activation energy. This is close to the energy needed for oxygen vacancy production next to a pair of Ce3+ on a CeO2 surface. These results may indicate a correlation between the O+ ESD yield and oxygen vacancy density on GDC surfaces and a potential correlation of O+ ESD and GDC ionic conductivity.