Harvest can be delayed because of inclement weather, breakdown of harvest machinery, or many acres ready to be harvested at the same moment. Delayed harvest can cause weather damage to wheat grain. This research was conducted to determine the effect of delayed harvest on semolina quality of durum wheat (Triticum turgidum L. ssp. durum [Desf.] Husn.). Twelve durum cultivars were used. They were classified as: old cultivars (Ben, Dilse, Lebsock, Mountrail, and Pierce), current cultivars (Alkabo, Divide, Grenora, and Strongfield), and new cultivars (Carpio, Joppa, and Tioga). Cultivars were planted in eight-row plots with four replicates at three environments. Two rows were harvested at each of four harvest dates. First harvest occurred when grain moisture reached 18%. Subsequent harvests were approximately one week apart. Semolina was evaluated for yellowness, protein content, wet gluten content, gluten index. Dough properties were evaluated using mixograph. Cultivar and harvest date had a larger effect than did environment on semolina quality. Harvest time main effect was significant and the trend for all cultivars was for an increase in gluten index and a decline in semolina yellowness, wet gluten, and mixogram peak width. New cultivars, ‘Carpio’ and ‘Joppa’, had the best semolina yellowness, while old cultivars, ‘Mountrail’, ‘Lebsock’, and ‘Ben’, had the lowest semolina yellowness. Delayed harvest time did not affect semolina protein content. ‘Carpio’ and ‘Joppa’ had a very strong gluten index and were affected least by harvest date; while gluten index of ‘Lebsock’ and ‘Grenora’ tended to be affected the most. In conclusion, delayed harvest was detrimental to semolina yellowness, wet gluten, and mixogram peak width. However, delayed harvest had a positive effect on gluten index.