In this study the mixed micelle behavior of an alkyl polyglycoside is compared to a surfactant of polyoxyethylene type, by means of surface tension measurements. The two nonionic surfactants are compared in mixed micelle systems together with an anionic surfactant, The surfactant mixtures are: decyl-beta-maltoside (C10M) with dodecyl benzenesulfonate (C12BS) and octaethyleneglycol mono n-decyl ether (C10EO8) with C12BS, The mixture of C10M and C10EO8 is also studied, Critical micelle concentration (CMC) and the concentration at which the surface tension reduction is 20 mNm(-1) (C-20) are determined at different mixing ratios of the surfactant mixtures. By applying the nonideal mixed micelle theory, interaction parameters at CMC (beta(CMC)) and C-20 (beta(20)) are calculated for the surfactant mixtures. The results show that the C10M-C12BS mixture has a beta(CMC) parameter of -2.1, whereas the beta(CMC) parameter for the C10EO8-C12BS mixture is -3.3, indicating a weaker net attractive interaction between C10M and C12BS than between C10EO8 and C12BS. This is attributed to a small negative and positive charge of the respective nonionic surfactants, This is supported by a slightly negative beta(CMC) parameter obtained for the surfactant mixture C10M-C10EO8, indicating a small net attractive interaction between the two nonionic surfactants.