The formation of protective layers on copper, zinc and copper–zinc (Cu–10Zn and Cu–40Zn) alloys at open circuit potential in aerated, near neutral 0.5 M NaCl solution containing benzotriazole was studied using electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). Benzotriazole (BTAH), generally known as an inhibitor of copper corrosion, also proved to be an efficient inhibitor for copper–zinc alloys and zinc metal. The surface layers formed on alloys in BTAH-inhibited solution comprised both polymer and oxide components, namely Cu(I)BTA and Zn(II)BTA polymers and Cu 2O and ZnO oxides, as proved by the in-depth profiling of the layers formed. A tentative structural model describing the improved corrosion resistance of Cu, Cu– xZn alloys and Zn in BTAH containing chloride solution is proposed.