Liquid-air interfacial tensions of representative alkanol + alkane and alkanol + amine systems measured by the differential capillary rise technique at 298.15 K are reported. The binary systems studied are hexane + ethanol and + 1-propanol, heptane + ethanol and + 1-propanol, and n-butylamine + methanol, + ethanol, and + 1-butanol. The excess surface tensions in the alkanol + alkane systems are negative, while in the alkanol + amine systems they are positive. The surface tensions themselves for the alkanol + amine systems, when plotted against mole fraction, exhibit a maximum. The two classes of systems exhibit characteristic patterns in their relative adsorptions. The results are discussed in relation to the bulk properties of these hydrogen-bonded systems.