Salinity is abiotic stress and is an effective factor in the production of all crops, especially in semi-arid and arid areas. Ascorbic acid (ASA) is an important antioxidant in plant tissues and has a great role in tolerance to various stresses. The aim of this work is to study the effects of ascorbic acid on growth traits, leaf photosynthetic pigments, biochemical attributes such as total phenolic content, isozymes electrophoresis and protein electrophoresis of three lupine cultivars under salinity stress. The effects of ascorbic acid on germination percentage and different growth parameters, as well as on chlorophyll pigments, total phenolics, electrophoresis of protein and isozymes profiles of esterase (EST), peroxidase (POX) and catalase (CAT) in three cultivars of Egyptian lupine (Giza 1, Giza 2 and Giza 3), which were grown under salinity stress using concentrations of NaCl (0 and 50 mM), were investigated. The results showed a significant decrease in germination and all growth parameters, as well as chlorophyll pigments (Chl a, Chl b) and total phenolics (TP). Also, salinity stress showed noticeable changes in isozymes profiles and an increase in the total number of protein bands in all cultivars. Application of ascorbic acid (ASA) caused an increase in shoot length (SL), root length (RL), seedling fresh weight (SFW) and seedling dry weight (SDW) in all cultivars compared to the salinity without ASA. Also, pretreatment with ASA led to increase of Chl a, Chl b and TP as well as led to the induction of new isozymes bands of EST, POX and CAT that may be related to the tolerance of lupine cultivars to salinity stress. On the other hand, ASA stimulated the appearance of new protein bands and the disappearance of others with different molecular weights under salinity in all cultivars. It could be concluded that soaking lupine seeds in ascorbic acid at a concentration of 200 mg/L before being exposed to salinity reduced the adverse effects of salinity stress by improving morphological and biochemical characteristics.