The implementation of proper agricultural practices is important for reducing the effect of salt stress in plants. Therefore, this experiment was conducted in 2014/2015 and 2015/2016 seasons at Ras Sudr station of Desert Research Center, South Sinai Governorate, Egypt, to determine the most effective selenium (Se) dose and application method on lettuce plants Bruma cultivar under salt stress conditions. Six different Se treatments; Se0 (without application as a control), Se1 (seed soaking in 30 µmol l^-1 for 12 h), Se2 (seed soaking in 50 µmol l^-1 for 12 h), Se3 (foliar application of 10 µmol l^-1), Se4 (foliar application of 20 µmol l^-1) and Se5 (foliar application of 30 µmol l^-1) were applied. The results showed that Se provision through both of the tested methods improved the plant leaf number, chlorophyll content, as well as N, P, K and Ca concentrations in the leaves, when compared with the control treatment. Moreover, Na content decreased in the leaves, which were treated than those of the control treatment. The plants grown under the Se treatments had larger heads and higher yields than the untreated plants. Foliar spraying was the most effective method of Se application of the lettuce plants, and the best results were obtained with the foliar spraying treatment at 20 µmol l^-1 sodium selenate. These results suggest that applying the appropriate dose of Se via foliar spraying has the potential for use as an efficient and practical method of improving plant growth and enhancing salt-stress resistance in lettuce plants.