Brassica are economically most important genus consisting of oilseeds, vegetables and forage crops. Brassica juncea L. commonly known as Indian mustard. The present study was carried out with 7-parents/strains (Varuna, Vardan, Basanti, Maya, NDR-8501-19, PR-21-15 and TPM-1) and 21crosses were obtained through diallel mating design (excluding reciprocal crosses). Total 28 genotypes (21 F1 + 7 parents) were investigated for 11 traits viz. days to 50% flowering, days to maturity, plant height (cm), length of main raceme (cm), number of primary branches per plant, number of secondary branches per plant, number of siliquae per plant, 1000-seed weight (g), protein content (%), oil content (%), and seed yield per plant (g). The estimates of average degree of dominance indicated presence of over-dominance for all traits. The variety Basanti and Varuna were found best general combiners in case of oil content in percent. The cross Basanti x PR-21-15 were found to be best for SCA for yield whereas, NDR-8501-19 x TPM-1 for oil content. Heterosis was observed in Vardan x PR-21-15 over better parent, while Maya x NDR-8501-19 showed heterosis over economic parent for yield.