The dynamic drop volume technique has been used to measure the dynamic interfacial tensions of nonionic surfactants (Triton X-45, X-100, X-165, and X-405) at the water/nonane and water/butylbenzene interface. The measurements were performed under the conditions of equilibrium distribution of the surfactant between the two liquid phases established after a sufficiently high number of aqueous solution drops have been formed within a small volume of the oil phase under study. The diffusion kinetics model for the description of the adsorption at the surface of growing drops involves equilibrium surfactant distribution and adsorption from both adjacent phases. Two orientational states of adsorbed surfactant molecule at the interface were assumed in agreement with recently published results at the water/air interface. Good agreement between this theory and the experimental data was obtained.