Surface photovoltage (SPV) needs to be considered in optical studies of electronic properties of semiconductor surfaces. We used a Kelvin probe (CPD), ultraviolet photoemission spectroscopy (UPS), and electric-field-induced Raman spectroscopy (EFIRS) to investigate the effect of SPV on adsorbate-induced variations of surface band bending at InP(110) and GaAs(110) surfaces at low temperatures. On InP(110) surfaces, which were exposed to Cs, H, and Cl2 at ≊170 K, the SPV was found to depend on the type of adsorbate and its coverage. After the light was switched off, the SPV was found to decay with time constants varying between some minutes up to a few hours. For GaAs(110) surfaces exposed to atomic hydrogen at 140 K, we observed the light of a discharge lamp to flatten the bands. By using EFIRS, on the other hand, the buildup of surface band bending was unambiguously detected as a function of exposure to atomic hydrogen. The H-induced changes of surface band bending determined from variations of the work function measured in the dark with a Kelvin probe and of the ionization energy evaluated from the widths of UPS spectra excellently agree with the EFIRS-derived data.