Vegetative parameters of eight M3 (third mutant generation) lines of sesame were evaluated under rain fed condition. The seeds of the lines were sown alongside their respective controls using a randomized complete block design. The eight lines were generated from three parental stocks: NCRIBEN-04E (V1), NCRIBEN-01M (V2) and NCRIBEN-03L (V3). The three parental stocks were exposed to different doses of gamma irradiation from cobalt-60 source. 04E-550-G2-3 had the highest plant height (57.40) at the 6th week which was significantly different (P<0.05) from the three checks. 03L-450-G2-2 had the highest petiole length (12.45cm) which was significantly different (P<0.05) from the checks except check three (12.25cm) which was not significantly different (P>0.05). 03L-450-G1-2 had the highest number of leaves (91) and consequently highest number of branches (5.60). Although the number of leaves were significantly different (P<0.05) from Check three (54.60), there was no significant difference (P>0.05) between the number of branches and check three (5.40). The results obtained for vegetative parameters of M3 lines of sesame suggests that some of the genotypes could be used as potential parents for future breeding programmes aimed at improving sesame lines.