Light and boron play a significant role in the physiological growth and yield of crops such as groundnut. Even so, there has been little information on the application of boron in groundnut, while no information is available in Bangladesh regarding the imposition of light in groundnut. Therefore, two field experiments were conducted in order to evaluate the physiological growth and seed yield of groundnut. Treatments included two levels of light, viz., L0 = normal day length (≈12-h light) and L = normal day length + 6-h extended light at night (≈18-h light); three levels of boron, viz., 0-kg B ha-1 (B0), 1-kg B ha-1 (B1) and 2-kg B ha-1 (B2), and two groundnut varieties, viz., V1 = ‘Dhaka-1’ and V2 = ‘BARI Chinabadam-8’. The results obtained from the experiment revealed that the highest LAI, LAR, LMR and RWR were recorded in L, B2 and V2 variants, while NAR was the highest in L0 and B0. Moreover, it was noted an inconsistent result for RGR found for boron application. Based on the results, it could be concluded that boron is one of the factors responsible for higher yield of groundnut; nevertheless, under the extended light, it is not possible to get the highest yield.