The piezo-optical coefficients P11-P12 and P44 have been measured for ZnSe and ZnTe above the fundamental gap (in the energy ranges 2.6-5.5 eV and 2.0-5.5 eV, respectively) by using reflectance difference spectroscopy. The measured spectra of P11-P12 and P44 show good Kramers-Kronig consistency between their real and imaginary parts. Values for the deformation potentials D1 5, D3 3, and D3 5 for the E1 and E1 + Î1 transitions were estimated by fitting the spectral dependence of P11-P12 and P44 to analytical line shapes based on a one-electron approximation.