The present research was accomplished during the two consecutive seasons of 2017-2018 and 2018-2019 at the Baramoon Experimental Research field, Dakahlia Governorate, Hort. Res. Institute, Agric. Res. Center, Ministry of Agric., Egypt. Therefore, an experiment was undertaken to examine the best treatment of some amino acids (Tryptophan, Arginine, Glycine and combination between them) as foliar usage at concentration of 100 ppm, beside the control treatment on enhancing vegetative characteristics, flowering and chemical constituents of dahlia (Dahlia pinnata L.) cut flowers (local variety). The results demonstrated that application of dahlia plants with a mixture of amino acids at 100 ppm as a foliar, accorded the highest plant height (81.1 - 86.0 cm), number of inflorescences (63.0 - 66.6), inflorescences fresh weight (15.59 - 16.70 g), inflorescence diameter (12.3 - 12.6 cm), total chlorophyll, total carbohydrates in leaves and flowers, N, P and K contents in the leaves. In addition, arginine at 100 ppm registered proclaimed considerable rates in vegetative and flowering parameters, pursued by plants sprayed by glycine in number of flowers then tryptophan in both seasons, respectively. The weakest values were obtained from untreated plants (control) in both seasons.