The present investigation was carried out to estimate genetic variability, heritability and GAM in inbred lines and hybrids. ANOVA indicated the availability of considerable variation for all the characters among inbred lines and hybrids except for ASI. PCV was higher than the GCV for all the characters. In inbred lines, important traits like plant height, number of grains per row, number of grains per cob, 1000-grain weight, grain yield per plant, dietary fibre, and β-carotene exhibited high PCV and GCV along with high heritability and GAM. Whereas, hybrids showed high values of PCV and GCV for ASI, phytic acid and high heritability coupled with high GAM were observed for traits like ASI, plant height, number of grains per row, number of grains per cob, shelling percentage, grain yield per plant, protein, dietary fibre, and β-carotene indicating the presence of variability in inbred lines and hybrids for these traits. Hence, simple selection for these traits in early generations for developing heat-tolerant maize lines can be practised.