Viscosities at T=(293.15, 298.15, and 303.15)K in the binary mixtures of ethyl tert-butyl ether with 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, and 2-[2-(2-ethoxyethoxy)ethoxy]ethanol have been measured over the entire range of mixture compositions. From the experimental data, deviations in the viscosity (Δlnη) and excess energies of activation for viscous flow (ΔG ∗E ) have been calculated. The viscosity data were correlated with equations of Hind et al., Grunberg and Nissan, Auslaender, and McAllister. The results for Δlnη and ΔG ∗E are discussed in terms of intermolecular interactions and structure of studied binary mixtures.