Background and Objective: Heat stress is one of the abiotic stresses that limit vegetable cultivations in the summer season especially with the extreme temperature due to climate changes. Therefore, this study established for evaluating the effect of glycine betaine and arginine as amino acids and concentrations of chitosan as a foliar application on cauliflower plants grown under high temperature. Materials and Methods: This work was carried out during the two summer seasons of 2019 and 2020 to investigate the effect of different amino acids sources (Control, glycine betaine at 250 ppm and arginine at 250 ppm) and different concentrations of chitosan(0, 250, 500 and 750 ppm) as a foliar application for alleviating the heat stress on cauliflower plants grown in sandy soil. Results: In both seasons, the results pointed out that glycine betaine significantly increased vegetative growth parameters, yield, head physical quality, leaves mineral contents (N, P and K), Leaf Relative Water Content (LRWC) (%), Membrane Stability Index (MSI) (%), total chlorophyll and nutritional values (vitamin C and crude protein) as compared to the other treatments. Adding 750 ppm chitosan was the most effective on growth parameters and pre-mentioned parameters. Conclusion: For alleviating the high-temperature effects on cauliflower plants grown in sandy soil, it should be used glycine betaine and/or 750 ppm of chitosan as a foliar spray.