Harvest can be delayed for many reasons. This research was conducted to determine the effect of delayed harvest on grain and semolina quality of durum wheat (Triticum turgidum L. ssp. durum [Desf.] Husn.). Twelve durum cultivars were planted in eight-row plots with four replicates at three environments. Two rows were harvested at four harvest times that were spaced about one week apart. The trend for all cultivars was for an increase in percent of large kernels, kernel brightness, 1000-kernel weight, and semolina gluten index with delayed harvest, while grain yield, test weight, kernel vitreousness, falling number, grain yellow pigment, and semolina yellowness and wet gluten content generally decreased. At all environments ‘Carpio’ tended to have high yields and ‘Strongfield’ low yields. ‘Carpio’ and ‘Joppa’ had the highest yellow pigment content and very strong gluten. In conclusion, grain and semolina quality generally declined with delayed harvest but varied with cultivar.