Zinc is one of the most used metal for galvanic coating, being applied on steel by hot dip galvanizing, electroplating or thermal spraying. The study of zinc electrodeposition is usually performed by interpreting polarization curves. Despite the efforts in investigating polarization curves, a number of gaps remain unfilled. This work performed a study on polarization curves for zinc deposition on steel. The experimental curves were obtained in an electrochemical cell following well-established procedures. The theoretical curves were modeled considering individual Butler-Volmer equations for each reaction. As results, qualitative and quantitative approaches of zinc deposition on zinc and on steel were established and a mechanism for interpreting the obtained polarization curves was proposed. A thermodynamic description for the occurrence of underpotential deposition was also presented. (C) 2019 Elsevier Ltd. All rights reserved.