Ion-beam-induced densification of sol-gel zirconia thin films is examined here. Ion irradiation of sol-gel zirconia films leads to microstructural and chemical changes (densification) in the films. Ion beam analysis indicates the loss of carbon, hydrogen, and oxygen as a result of implantation. Oxygen:zirconium ratios less than that predicted for stoichiometric ZrO2 for the higher dose implanted films were observed. The chemical and microstructural modifications were attributed to both electronic interactions and nuclear collisions between the energetic ions and the target atoms. Densification of only a near-surface region of a sol-gel zirconia thin film proved that the effects of beam heating on the observed densification are minimal.