Quasi-steady state hydrodynamic voltammetry at a rotating-disc electrode and electrochemical impedance spectroscopy were used to investigate the influence of triethyl-benzyl-ammonium (TEBA) chloride on the kinetics of copper electrodeposition from sulphate acidic electrolytes. SEM and X-ray diffraction analysis were used to examine the morphology and the structure of copper deposits. The kinetic parameters (i(0), alpha(c), k(0)), obtained by both Tafel and Koutecky-Levich interpretations lead to the conclusion that TEBA acts as an inhibitor of copper electrodeposition process, as a consequence of its adsorption on the electrode surface. The influence of TEBA on the kinetics of copper electrodeposition was explained in terms of a reaction model confirmed by the simulated impedance spectra. TEBA acts only as a blocking agent competing for adsorption active sites of the cathodic surface with cuprous ions without changing the reaction pathway corresponding to the absence of the additive.