An emission line in GaP of previously unexplained origin peaking at about 1.96 eV (6300 Å) at 77°K was studied in electroluminescence of forward biasedp‐njunctions and in photoluminescence. We attribute this band to the presence of Si. The peak energy position of the 1.96‐eV band is dependent on the identity of the dominant shallow donors, thereby indicating that the deep center is an acceptor. The results indicate that Si substitutes at Ga sites and acts as a shallow donor. At high‐electron concentrations, Si causes the appearance of an acceptor with a level about 0.25 eV above the valence band. The dependence of current and light intensity on voltage was studied. The 1.96‐eV line has an external quantum efficiency at 77°K of up to 1.4×10−2but is rapidly quenched with increasing temperature.