Divergent phenotypic selection was performed for flag leaf angle (FLAN) under heat stress in five F₂ populations of bread wheat (Triticum aestivum L.). Direct responses for FLAN and correlated responses for grain yield per plant (GYP) and thousand kernel weight (TKW) were measured. FLAN was positively and significantly correlated with GYP and TKW under heat stress. Positive and highly significant (P<0.01) responses to selection for FLAN were obtained in both directions for the five populations, which were higher in magnitude in the low direction (averaged 31.41) than those obtained in the high direction (averaged 22.0%). Selection for high FLAN produced concurrent positive and significant (P<0.05) responses in GYP in only two populations, with an average of 5.17%, which was lower in magnitude than averaged correlated responses (8.24%) obtained in GYP for lower FLAN in four populations. Significant (P<0.05) correlated responses to selection in TKW for higher FLAN were obtained in four populations (averaged 4.03%) and were smaller in magnitude than those obtained for lower FLAN (averaged 9.56%). Additive gene effects were found to be mainly controlling FLAN. Moderate realized heritability estimates obtained for FLAN (averaged 0.53) were similar to heritability obtained by parent-offspring regression (averaged 0.50). Bulked segregant analysis (BSA) using twelve simple sequence repeats (SSR) markers for FLAN identified three SSR markers, namely Xgwm294-2A; Xbarc113-6A and Xwmc398-6B were able to distinguish high from low bulks in at least two populations. Three bands specific for high and two specific for low FLAN were generated, that could be used in the future as markers associated with FLAN under heat stress in wheat. The information presented here could help in understanding the genetic system controlling FLAN and its relationship with grain yield under heat stress.