Measurements of the thermal conductivity (k) of solid oxygen doped with nonmagnetic impurities of N₂ (0.34 and 0.94%) and Ar (1%) were made in the temperature range 1-35 K. It was shown that in the antiferromagnetic alpha phase doping with nonmagnetic impurities has a drastic effect on low-temperature thermal conductivity which supposedly is a result of suppression of the magnon contribution to the heat transport by the impurities. At the same time, the jump in the thermal conductivity at the alpha - beta transition and the thermal conductivity in the beta phase are practically insensitive to the doping effect which we attribute to strong magnetostriction effects characteristic of the beta phase.