Nanoparticles that fluoresce or absorb light in the visible and near-IR wavelengths are desirable for a variety of applications including biological tagging for medical imaging purposes and for solar control glazing in the automobile industry. Semiconductor quantum dots are commercially available and dyed polymer nanoparticles as well as organic dye/silica core shell nanoparticles have also been demonstrated. We report the synthesis, characterization, and optical properties of another luminescent nanoparticle: doped zirconia. The zirconia nanoparticles reported in this study are doped with up to 10% of the lanthanide dopants Er, Gd, Nd and Eu. These materials emit in the visible and near-IR wavelengths depending on the dopant and are refractory, making them useful for high temperature applications. These cations were found to stabilize the cubic phase over the monoclinic phase of zirconia, at approximately 10% dopant, as characterized by X-ray diffraction. We report the luminescence spectra of these nanoparticles at various wavelengths which reveal emissions from the matrix as well as from the dopants.