We have investigated the magnetism of 0.5 at. % ${\mathrm{Fe}}^{\mathrm{3+}}$ -doped CuO samples by Mössbauer spectroscopy and magnetization studies. The Curie–Weiss-type behavior observed for low-field-magnetization measurements at temperatures higher than 220 K is interpreted as an uncompensation of moments enhanced by the doping. The results are compared with 1.2 at. % ${\mathrm{Zn}}^{\mathrm{2+}}$ -doped CuO magnetization results and previous ones for samples doped with divalent ions. Trivalent ion doping produces an increase in the susceptibility with a peak at $T_N.$ The magnetic coupling of ${\mathrm{Fe}}^{\mathrm{2+}}$ ions to the magnetic lattice is found to be about four times stronger than that of ${\mathrm{Fe}}^{\mathrm{3+}}.$