Thin wetting films from aqueous solution of four polyoxyalkylated diethylenetriamine (DETA) polymeric surfactants (named A, B, C, and D) are studied. Surfactants A, B, and C have a star-like structure differing only by the number of polymeric branches: four, six, and nine in the mentioned order while the forth one, D, is of a dendritic type with four to six primary and two to three secondary branches. The receding contact angles θ r of the solution on hydrophilic SiO 2 glass surface and the contact angle θ aq of a drop of doubly distilled water on SiO 2 glass surface pretreated with DETA polymeric surfactant solution are measured. The θ r values on hydrophobicity of SiO 2 glass surface, respectively, increase in the following order: surfactant A, surfactant C, surfactant B, and surfactant D. The equilibrium thickness h eq of wetting films from DETA aqueous solution on hydrophilic SiO 2 glass surface is measured using the micro-interferometric method. Results show an unexpected course of the h eq vs. C s curves with a maximum. Results from the studies indicate that differences in polymeric surfactant molecular structure affect the properties exhibited at air/liquid and solid/liquid interfaces, such as the value of surface tension, degree of hydrophobicity of solid surface, equilibrium film thickness, etc.