Lithium doping has a dramatic effect on the low‐temperature photoluminescence of electron‐irradiated Si. In oxygen‐lean Si with Li doping, a new irradiation‐dependent luminescence band between 0.75 and 1.05 eV is observed, which is dominated by a zero‐phonon peak at 1.045 eV. This band is believed to be due to radiative transitions involving a Li‐modified divacancy. This band is present also in oxygen‐rich, Li‐diffused Si and is accompanied by bands previously related to the si‐G15 (K) center and the divacancy. The intensities of the Li‐modified divacancy and Si‐G15 (K) center bands are relatively weak in the oxygen‐rich material, apparently due to the formation of lithium‐oxygen complexes which reduce the concentration of unassociated interstitial Li and O.