AbstractThe lipophilicity (RM), specific hydrophobic surface area and the relative strength of interaction between trimethyl‐β‐cyclodextrin and 39 nonionic surfactants having different hydrophobic moieties has been determined by charge‐transfer thin‐layer chromatography using methanol as an organic modifier. RMvalues decreased linearly with increasing concentration of methanol. The significant correlation between the RMvalue extrapolated to water and the specific hydrophobic surface area indicates that these surfactants can be considered from the chromatographic point of view as a homologous series of solutes independently of their structural inhomogeneity. Stepwise regression analysis suggested that the length of alkyl chain in the hydrophobic moiety, the presence of sorbite and phenyl group in the surfactant molecule, and the number of ethyleneoxide groups per molecule have the highest impact on their hydrophobic parameters. The relative strength of surfactant‐cyclodextrin interaction significantly depended on the lipophilicity of the surfactants, and on the presence of phenyl group and ester bonds in the surfactan