Grain protein content and amino acid composition of wheat vary greatly depending on the genotype and environment. The objectives of this work were to determine the variation in the amino acid composition of the grain of 10 durum wheat genotypes grown under different water and temperature regimes under Mediterranean conditions. Analyses of variance for amino acid composition, grain yield and protein content showed that water availability during crop growth had a greater effect than genotype or genotype×environment interactions. The relative contents of glutamine and proline were higher in the rain-fed environments, probably due to a decrease in the duration of grain filling and faster leaf senescence, conditions that promote an earlier synthesis of gliadin + glutenin during grain development, proteins especially abundant in glutamine and proline. In contrast, the relative amounts of the other amino acids tended to decrease with the reduction in the duration of grain filling, particularly for tyrosine, lysine, phenylalanine and methionine. These amino acids are particularly abundant in albumins and globulins, proteins mainly synthesized during the first phases of grain development and whose synthesis would finish early under conditions that shorten the duration of grain filling.