Climate change on a global scale and an expanding human population have disturbed food security globally. One of the main abiotic factors affecting the productivity and quality of barley is heat stress. The aim of this study was to evaluate the performance of fifteen barley genotypes for heat stress and yield traits under two sowing dates, timely and late sowing (10th November and 10th December) during the 2022-23 and 2023-24 seasons. The current work was conducted at the Experimental Research Station, Faculty of Agriculture and Natural Resources, Aswan University, Egypt. The genotypes were grown in a Randomized Complete Block Design (RCBD), with three replications. The obtained results revealed that the sowing date on 10^th November recorded the highest mean values for flowering date, number of spikes m^-2, number of grains spike^-1, 1000-grain weight, and maturity date in the first and second seasons, respectively. Data indicated that genotype Giza 126 (G₃) recorded the highest average values of seed yield as 3,213 and 2,815 kg fed^-1 under timely sowing date (10^th November). In contrast, the lowest mean values of seed yield were recorded from G₁´G₂ (2,219 and 1,699 kg fed^-1) and G₁´G₄ (1,953 and 1,654 kg fed^-1) in the first and second seasons, respectively. The genotypes Giza 126 (G₃), G₃×G₄ and G3×G5 significantly outperformed all studied genotypes for grain yield under both timely and late sowing dates. From the results of heat tolerant indices, Giza 126 (G₃), G₃´G₄, G₃´G₅, and G₄´G₅ were considered as tolerant genotypes to heat stress because they exhibited higher values for mean productivity (MP), geometric mean productivity (GMP), tolerance Index (TOL), stress susceptibility index (SSI), and yield Index (YI), and lower values of yield stability index (YSI).