Heat stress is an important abiotic stress causing the major threat to the growth and development of most crop plants. A panel of 326 barley genotypes comprises of 320 wild barley accessions and six local cultivars were evaluated for days to heading (DTH), days to flowering (DTF), number of tillers per plant (NoT), plant height (PH), Chlorophyll content (CC), spike length (SL), thousand kernel weight (TKW) and single plant yield (SPY) under optimum sowing and heat-stressed conditions. All measured traits exhibited highly significant differences both among evaluated genotypes and between the optimum sowing and the heat-stressed conditions. Plants exposed to high temperatures flowered earlier. A drastic reduction in morphological and yield contributing traits, i.e., PH, NoT, SL, TKW, SPY and CC under heat stress conditions was observed. Cluster analysis revealed two distinct groups based on heat stress tolerance with substantial diversity among the heat tolerant genotypes.