Genetic basis of tolerance to high temperature is important for improving the productivity of wheat (Triticum aestivum L.) in heat stress regions. In present investigation out of 54 wheat cultivars/lines screen for terminal heat stress ten cultivars/lines classified as highly tolerant, tolerant, moderately tolerant, and susceptible to heat stress were mated in diallelfasion to generate 45 F1 hybrids which were evaluated using RBD in both normal and heat stress conditions at Banaras Hindu University, Varanasi, India. Genetic parameters for morpho-physiological traits viz., days to 50% heading, plant height, grain number spike-1, 1000 grain weight, grain yield plant-1, canopy temperature depression (CTD), cell membrane thermostability (CMS) and heat susceptibility index (HSI) were estimated. The magnitude of SCA variance was greater than GCA variance for most of the traits. The additive (D) and dominance components H1 and H2were highly significant for all the traits in both environments. Proportion of gene (H2/4H1) with positive and negative effects in the parents demonstrated an unequal distribution of dominant genes in the parents for almost all the traits. For CTD and CMS h2(ns) estimate were high. Whereas moderate for day to heading and plant height.