Sulfur functionalized polyalphaolefins (PAOs) comprising at least one SCH.sub.2C(R.sub.1R.sub.2)S moiety, wherein R.sub.1 and R.sub.2 are independently selected from linear or branched alkyl, are provided. The sulfur functionalized polyalphaolefins (PAOs) are prepared by contacting PAO with elemental sulfur and are useful as lubricating oil base stocks or co-base stocks. The sulfur functionalized PAOs exhibit high oxidative stability and can be prepared without the need for hydrogenation.