The electronic and optical properties of Ge‐doped vapor epitaxial indium phosphide were studied. From Hall‐effect measurements, it was determined that the Ge‐doped material was heavily compensated even for highly doped material. The defects responsible for compensating the InP were investigated by low‐temperature photoluminescence measurements at 10 K. Strong acceptor‐related transitions at 1.379 and 1.395 eV were observed in the doped material. Deep‐level emission at 1.17 eV was also observed in the heavily doped material. The relationship between these bands and compensation is discussed. The observed doping dependence of Ge in InP suggests that self‐compensation by native defects may be important in determining the electronic properties of group IV doped III‐V compounds in support of recent theoretical predictions.