This paper explores the possibility of measuring the open-circuit voltage of a solar cell as a function of wavelength as a tool for device characterization. Theoretical calculations and computer simulations show that the spectral response of the open-circuit voltage exhibits a similar dependence to the spectral response of the short-circuit current. Experimental studies on silicon solar cells confirmed the strong spectral dependence of the open-circuit voltage. The spectral measurements have been performed using a quasi-steady-state open-circuit voltage method, which also allows to determine the spectral response of the maximum power voltage. The advantages of this new technique over conventional spectral response measurements include its applicability directly after junction formation and the simplicity of the experimental apparatus. (C) 2003 Elsevier B.V. All rights reserved.