This study aimed to assess the responses of selected irrigated bread wheat lines and the commercial cultivar Mihan to terminal drought stress (irrigation withholding during grain filling) in the 2023-2024 growing season in Bukan, Iran (temperate-cold climate, annual rainfall 250 mm). The experiment used a randomized complete block design with split-plot arrangement and three replications: main plots were irrigation levels (well-watered vs. cutoff at grain filling), and subplots were seven genotypes (lines 5118, 5209, 5013, 5216, 5005, 5220, and Mihan). Drought stress significantly affected days to maturity and thousand-grain weight (p<0.05), grain yield, and grains per spike (p<0.01). Genotypic effects were significant (p<0.01) for all traits except harvest index. Line 5005 showed the highest grain yield (9213 kg ha⁻¹ well-watered; 9044 kg ha⁻¹ stressed), grains per spike (64-66), stress tolerance index (STI=9140), and geometric mean productivity (GMP=9176.7 kg ha⁻¹), identifying it as the most tolerant and stable genotype. Line 5216 exhibited the least reduction in grain weight under stress. Average grain yield reduction was 1.57%, indicating mild stress impact and genotypic variation in drought response differentiating this from studies reporting 20-30% losses. Line 5005 is recommended for drought-prone cultivation and as a resistant parent in breeding programs.