It is shown in this paper that the wetting behavior of n-alkanes on a water surface can be predicted using the wetting theory of Cahn, together with experimental results for n-alkane vapor adsorption on water which are readily available in the literature. The evolution of the wetting behavior with the carbon number of linear alkanes and with temperature is determined and wetting temperatures are calculated. The results agree with experimental observations at room temperature, except for pentane which appears to be a limiting case. The determination of the wetting temperature demonstrates that in order to account for the wetting behavior, additional effects of long-range forces have to be taken into account.