Plants show physiological, morphological and chemical responses to microbial, physical or chemical factors which are known as elicitors. Water deficit stress is one of the most important abiotic stresses that affects plant physiological and morphological traits. Chitosan is a natural, less toxic and economical compound that is biodegradable and eco-friendly with various applications in agriculture. The present experiment was carried out to evaluate the effect of pre-harvest foliar application of chitosan on quality indices of tomato plant under different water stress conditions. Tomato (Cv. Rio Grande) plants were subjected chitosan concentrations (0, 50, 100,150 mg L-1) and water stress intervals (3, 6, 9 and 12 days) after 15 days of transplantation. Tomato plants treated with 6 days water stress interval recorded maximum fruit firmness, fruit juice content, total soluble solids, titratable acidity and ascorbic acid content and minimum of fruit juice pH. Similarly, chitosan application @ 100 mg L-1 attained highest fruit firmness, percent juice content, total soluble solid, titratable acidity, ascorbic acid content and minimum fruit juice pH. It is concluded that 100 mg L-1 chitosan application along with 6 days water interval had positive impact on quality indices of tomato.