A field experiment was conducted during the (rabi) seasons of 2009–2010 and 2010–2011 at the research farm, Department of Agronomy, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, to find out the suitable row ratio of Indian mustard (Brassica juncea L.) intercropping with wheat (1:9, 2:9, 1:6, 2:6) and lentil (1:4, 1:5, 2:4, 2:5) row ratios, respectively. The highest yield attributes of mustard were recorded with mustard + lentil (2:5), which was significantly superior to mustard + wheat (1:9) and mustard + lentil (1:5). Maximum seed yield and stover yield of mustard was recorded with mustard + lentil (2:4), which was being significant over other row ratios of mustard + wheat (1:6, 1:9, 2:9) but was at par with mustard + lentil (1:5) and mustard + wheat (2:6) row ratios. Mustard equivalent yield (3128 kg ha−1) recorded under intercropping of mustard with wheat in 1:9 row ratio was significantly higher than sole cropping of mustard, wheat, and lentil, and other remaining intercropping systems. Intercropping of mustard with wheat in 1:9 row ratio showed the highest land equivalent ratio (1.51), aggressivity index (+0.15), net return (60,468 Rs ha−1), and benefit:cost ratio (4.3) among all other intercropping treatments.