Gmelina arborea-based agroforestry provides farmers with increased economic benefits, improves soil health, helps counteract the decline in national forest cover, and offers raw materials for both industrial use and local community needs. The study examined three different spacings of Gmelina arborea: 5 m × 5 m, 5 m × 4 m, and 5 m × 3 m, under two growing conditions: sole cropping and intercropping. Data analysis revealed that lentil varieties grown in open conditions exhibited better growth and yield attributes than those grown in agroforestry. The analysis of various growth and yield characteristics indicated that growing environment significantly affected plant growth and yield attributes. Specifically, parameters such as plant height (37.76 cm), number of primary branches (5.34), root nodules per plant at 90 days after sowing (1.23), dry matter accumulation (9.43), days to physiological maturity (124.43), days to 50% flowering (77.1), pods per plant (87.6), straw yield (1732 kg ha-1), grain yield (1014 kg ha-1), and biological yield (2746 kg ha-1) were all higher in sole cropping as compared to agroforestry. IPL 316 lentil variety performed better compared to L 4727 in both cropping systems. Overall, Gmelina arborea-based agroforestry yielded greater economic returns than sole cropping.