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We have measured the absolute values of the second-harmonic generation ͑SHG͒ coefficient ͉d͉ for the zinc-blende II-VI semiconductors ZnTe, ZnSe, and ZnS at room temperature. The investigated spectral region of the fundamental radiation F ranges from 520 to 1321 nm using various pulsed laser sources. In the transparent region of the II-VI semiconductors, the SHG coefficient exceeds the values of birefringent materials as ammonium dihydrogen phosphate ͑ADP͒ and potassium dihydrogen phosphate ͑KDP͒ by one or two orders of magnitudes. Above the E 0 band gap a strong dispersion of ͉d͉ is observed, showing a maximum for a second-harmonic frequency close to the E 1 gap. The experimental results are compared to calculated values using a simple three-band model including spin-orbit splitting. Substantial agreement is found to the experimentally observed dispersion of the second-order nonlinear susceptibility. ͓S0163-1829͑98͒06539-4͔