Ag-, Ce- and Ga-promoted Cu–Mg–Al hydrotalcite derived mixed metal oxides were obtained by standard coprecipitation, followed by calcination. The obtained Ag(Ce, Ga)–Cu–Mg–Al–O_x mixed metal oxides were characterized with respect to their crystalline structure (XRD, TEM), texture (BET), surface acidity (NH₃-TPD), redox properties (H₂-TPR), chemical surface composition (XPS), and tested in the selective catalytic oxidation of ammonia into nitrogen and water vapour (NH₃-SCO). The loading of Ag_y-, Ce_y-, or Ga_y–Cu₅–Mg_66−y–Al₂₉ (y = 0–1) had a clear effect on the catalytic performances. For materials with low metal loadings (y ≤ 0.25), the redox properties determined the catalytic performances in NH₃-SCO. The formation of easily reducible CuO_x played a crucial role for enhanced catalytic activity at lower temperatures, with a drop in the selectivity to N₂ at higher temperatures. Higher metal loading (y ≥ 0.5) led to the formation of surface and bulk copper oxide species, and other aggregated metal oxide phases, which enhanced the catalytic activity for Ag–Cu–Mg–Al–O_x, and diminished activity for Ce(Ga)–Cu–Mg–Al–O_x.