The 6 × 6 half-diallel crossings among six parental lines for twelve traits were investigated to estimate different genetic parameters and identify superior lentil line combinations. The significant results of the analysis of variance for all the traits except RW proved the parental lines genetically different from each other. Dominance and additivity were studied and over dominance was found in NPBFF, CAMF, NPdPP, NSPP, SWPP and IPW through Wr/Vr and (Wr + Vr′)/Yr′ graphs. The degree of dominance (H1/D)1/2 supported the result of over dominance for all the traits. The asymmetry in the proportion of genes with positive and negative effects in the parents was studied for all the traits and the presence of an excess dominant gene in most of the traits was noted. General combining ability (GCA) for DFF, PHFF, NSBFF, CAMF, NSBMF, NPdPP and NSPP, as well as specific combining ability (SCA) for all the traits except NPBFF and RW were significant indicating the importance of additive and non-additive gene action, respectively. Parents P3, P4 and P5 were assessed as good general combiner from this investigation and the crosses viz. P1 × P2, P1 × P3, P2 × P5, P4 × P5 and P5 × P6 were the best combiners as judged from the specific combining ability effects. So, these parents and crosses need special consideration for the improvement of lentil.