The effect of the nature of calix[n]arenes [n = 4, 6, 8] added to a plastic lubricant on the oxidation resistance of the lubricant at high temperatures is studied. Such characteristics as the number of phenolic fragments in the calixarene structure, the presence of tert-butyl groups on the upper rim of the calix[n]arene, and presence of an O-alkyl substituent in the lower rim are examined. It is shown that calix[8]arenes are capable of inhibiting high-temperature oxidation of plastic lubricants, regardless of the presence of a tert-butyl substituent on the upper rim and an alkyl substituent on the lower rim.