The present study was conducted during 2019 and 2020 seasons in the Experimental Farm of EL-Quassassin, Horticulture Research Station, Ismailia Governorate, Egypt to investigate the effect of foliar application of glutamic acid on sweet basil (Ocimum basilicum, L. var. Grand Vert) plants grown under different irrigation levels. A split-plot design was used, the main factor was irrigation levels (50%, 75% and 100% of crop evapotranspiration (ETc)), while the glutamic acid at (0, 5 and 10 mM) were assigned in sub-factor. The results showed that irrigation rates had a significant effect on most aspects for the two cuts in both seasons. Where the irrigation level at 100% ETc was the most effective treatment. The foliar spraying with glutamic acid on sweet basil plants had a positive effect on plants, it significantly increased growth, yield parameters and chemical composition in treated plants as compared to un treated ones. Regarding the interaction treatments, it was worth to be mentioned that, there was insignificant difference, when spraying with glutamic acid under irrigation level at 100 or 75% ETc in most studied traits. Also, the results of Gc- Ms analysis of sweet basil volatile oil indicated that, the highest linalool content which consider the main component was produced with irrigation level at 75% ETc +spraying with 10mM glutamic acid. Furthermore, glutamic acid foliar application improve irrigation water utilization efficiency (IW.Ut.E). The highest IW.Ut.E was recorded at the interaction of irrigation level at 50% ETc with foliar application by10mM glutamic acid.