Both the anti-Stokes and Stokes emission properties of cubic Y2O3:Ho3+ arising from excitation at a wavelength of 632.8 nm are reported over the concentration range 0.25 - 10 mol % Ho3+. Power dependence studies are used to assign the bands in the emission spectra. The most efficient yellow-green upconversion emission was observed at a Ho3+ concentration of 0.5 mol %. This originates from an absorption process involving two photons and undergoes progressive quenching as the Ho3+ concentration is increased. It is shown herein that as the concentration of Ho3+ is increased, cross-relaxation processes become dominant. These processes involving Ho3+ ions in the F-5(5) levels and the metastable I-5(7) states enable an alternative process for the population of the K-3(8), F-5(3), and F-5(2) levels that gives rise to enhanced emission between 480 and 505 nm as the concentration of Ho3+ ions is increased from 0.5 to 10 mol %. This cross-relaxation process is discussed in the text. In this work we also report the first discrimination between emission bands due to transitions originating from the F-5(4) and S-5(2) levels of Ho3+. The emission bands originating from the F-5(4) level (viz. the yellow-green 530-570 nm and the near-infrared 740-780 nm bands) are shown (as expected) to have a similar dependence on the incident photon flux.