The promising structural features of the defect spinel-type oxide γ-Ga2O3 and its application potential as a host for new nanoscale solid solutions have been far less explored than its analog γ-alumina, which is widely used in catalysis. Therefore, new synthetic approaches are required to access transition metal-doped γ-Ga2O3 materials on the nanoscale. We have established the first microwave–hydrothermal route for the challenging incorporation of Cu2+ ions into a nanostructured γ-Ga2O3 matrix. Homogeneous γ-Ga2O3:Cu2+ materials with high surface areas are formed within less than 30 min, and the copper content can be adjusted through the synthetic parameters. The copper distribution within the spinel matrix was analyzed with a wide range of compositional, structural, spectroscopic and magnetic characterizations.