This study compares the solid-state hydrogenHydrogen-reductionReduction of pure CuOCuO and a synthetic copper slagCopper slag, both prepared from high-purity commercial powders. The synthetic slag composition was 39 wt% SiO2, 26 wt% Fe2O3, 25 wt% CaO, 5 wt% Al2O3, and 5 wt% CuOCuO. Both materials were pelletized and reduced at 1000 °C for 5 to 20 min in a horizontal tube resistance furnace under 15% H2/Ar gas flowing at 300 ml/min. Complete reductionReduction of CuOCuO to metallic Cu was achieved within 20 min for pure CuOCuO and within 15 min for the CuOCuO in synthetic slag. In the slag samples, SEMScanning Electron Microscopy (SEM)-EDS analysis showed that Fe2O3 reductionReduction occurred gradually after the complete reductionReduction of CuOCuO, as no metallic Fe was found in samples reduced between 5 to 15 min. These findings show that in complex oxide systems, hydrogenHydrogen selectively reduces CuOCuO prior to Fe-oxides thereby demonstrating the feasibility of hydrogenHydrogen-based reductionReduction for selective copper recovery from iron-bearing slags. These experimental results were also supported by thermodynamicThermodynamic modelling results that show the selectivity of copper oxide reductionReduction into copper in the slag prior to iron oxide.