The present investigation entitled “Effect of high temperature on growth and yield attributes of Indian mustard genotypes due to late sown” was conducted in randomized block design (RBD) with 12th new promising mustard genotypes viz., Vardan, Ashirwad, NPJ-207, NPJ-208, RGN-403, PBR-417, DRMRIJ 16-3, DRMR-2035, RRN-911, RH-1556, RGN-368 and BPR 541-4 widely differing in their growth behavior during two consecutive years (2017-18 and 2018-19). Study their genotypic variability for morphological, yield, and its attributes under late sown conditions. Results revealed that growth in terms of plant height, biomass accumulation, branching behavior, leaf area, growth parameters, yield, and its components varied significantly among tested mustard genotypes during both years of study under late-sown conditions. Findings indicated that mustard genotypes viz., DRMRIJ 16-3, RGN-403, and RH-1556 recorded higher values of total branches plant-1, leaf area (cm2), dry matter accumulation at harvest (g), siliquae on different branches, number of seeds/siliqua, seed yield/plant, biological yield per plant, test weight, harvest index as compared to other genotypes under late sown condition.