Optical transmittance measurements near the absorption edge in the energy range 3.4–6.4 eV have been carried out on (NH4)2ZnCl4:xSr2+ single crystals with x=0.000%, 0.020%, 0.039%, 0.087% or 0.144%. The introduction of Sr2+ in low concentration, x=0.02% or 0.039%, little bleach the intense charge transfer band observed for the undoped sample with a maximum at 5.30 eV. Doping with Sr2+ in a little bit higher concentration, x=0.087% or 0.144%, led to the disappearance of this band. While doping with Sr2+ has no effect on the indirect allowed type of optical transition in AZC, the optical energy gap decreased with increasing Sr2+ concentration. Measuring reflectance of AZC permitted the calculation of the refractive index n, the extinction coefficient K and both the real r and imaginary i components of the dielectric permittivity as functions of photon energy. The validity of Cauchy–Sellimaier equation was checked in the wavelength range 5.45–5.8 eV and its parameters were calculated. Applying the single-effective-oscillator model, the moments of (E) could be estimated. Electric susceptibility, as a measure of intraband transition, was calculated and its dependence on photon energy was considered