The current study was conducted to evaluate the effect of foliar application of salicylic acid treatments on growth, yield and quality of lettuce plants cv “Big Bell" that grown under water deficit stress. A field experiment was carried out during 2018-2019 and 2019-2020 seasons at the Experimental Farm, Faculty of Agriculture, Cairo University, Egypt. Drought was induced by withholding watering for 15 days after salicylic acid (SA) application exactly at 20 and 30 days after trasplanting. Five treatments were utilized. These were water-stressed +100 ppm of SA, water-stressed +200 ppm of SA, water-stressed +300 ppm of SA foliar spray, water-stressed only, and the fifth group served as control. Results indicated that water stress adversely affected growth and productivity parameters of lettuce cultivar “Big Bell". Water stressed plants at earlier stage of growth (20 day stage) were more inhibitory as compared with the plants at the age of 30. Generally, foliar spraying with salicylic acid significantly protected against the stress and increased root length, root weight, fresh head weight, head diameter,photosynthetic pigments compared to treatment that under water deficit. However, proline content increased under drought as well as under SA treatments. Spraying of salicylic acid at 200 ppm at the age of 30 was the most effective treatment that causing significant increase in yield by18.31% and 26.9% relative to control treatment in the first and second seasons, respectively. Application with salicylic acid increases drought tolerance and avoids the deleterious effect of water stress.