Vibrational-state selective cross sections have been measured for the endothermic charge-transfer reactions H+,D++HCl(X 1∑+)→H,D(2Sg)+HCl +(A 2∑+,v′)−2.67 eV, for collision energies up to 1 keV by means of detecting the spontaneous optical emission of the HCl+(A 2∑+,v′→X 2Πi, v″) band system. Absolute values between 0.25 and 1 Å2 were obtained by calibration against the known cross section for electron-impact ionization of N2 with subsequent emission of the N+2(B,v′→X,v″) transition. The charge-transfer cross sections were also calculated using the Landau–Zener theory. The required model parameters were derived from recent ab initio calculations. The energy dependence and the relative magnitude of the cross sections for the product vibrational levels v′=0–5 were closely rendered by the theoretical curves in the velocity range where the Landau–Zener approach applies, i.e., below 200 km/s (≡200 eV for protons). The absolute magnitude of the calculated cross sections also agrees with the measurements within the experimental error limits.