Fennel (Foeniculum vulgare Miller.) in an important medicinal and aromatic fruits used in nutrition pharmaceutical industries. The main objective of this investigation was to elucidate the influence of ascorbic and salicylic acids on optimizing growth and yield performance of fennel grown under three different irrigation levels (60, 80 and 100%) based on ETc during two seasons of 2021 and 2022. Growth characteristics (plant height, shoot number, fresh and dry weight) were found to be highest at 100 or 80% ETc and 300 ppm ascorbic acid. While, they found to minimize with 60% ETc and 100 ppm salicylic acid. Besides, different yield performance parameters such as 1000 fruit weight, fruits and essential oil yield were also significantly influenced by irrigation levels and organic acid application. Maximum results found to be 9.73 and 10.41 g for thousand fruits weight, 2.10 and 2.05 ton for fruits yield per feddan and 52.59 and 53.20 litter for essential oil yield per feddan which were recorded with irrigation level 100% ETc and 300 ppm ascorbic acid in the two seasons, respectively. Followed by 80% ETc with same rate of ascorbic acid.  Antioxidant activity and total phenols increased significantly by increasing in water stress.