In this investigation, the direct catalytic decomposition of N2O into N2 and O2 was performed over CuxCo1−xCo2O4 (x = 0.0 ≤ x ≤ 1.0) spinel-oxide catalysts. These catalysts were synthesized by the co-precipitation method followed by calcination at 500 °C. The activity results demonstrated that the partial replacement of Co2+ by Cu2+ in the spinel-oxide Co3O4 led to a significant improvement in the N2O decomposition. Additionally, the activity was found to be controlled by other parameters, including the size of the spinel crystallites, the surface area of the catalysts, and the presence of residual potassium ions.