This experiment was conducted during the summer seasons of 2015 and 2016 to investigate the effect of various water irrigation levels (60%, 80% and 100% from ETo) and some foliar application treatments (chitosan, salicylic acid, silicon and proline) and their interactions on vegetative growth characteristics and leaf chemical constituents of tomato plants (Solanum lycopersicum L) " Fayruz " hybrid under surface drip irrigation system in a private farm at Gemiana village near El-Mansoura city, Dakahlia Government, Egypt. All treatments under investigation significantly affected vegetative growth parameters, i.e., plant height, number of branches, number of leaves, leaf area, fresh and dry weights, as well as chemical constituents of leavesas photosynthetic pigments (Chl. a, Chl. b and total Chl. a+b), leaf minerals content (N, P and K), proline and peroxidase activity. Results indicated that the highest values of all aforementioned parameters except proline and peroxidase were recorded when plants irrigated with 80% from ETO compare to 60% and 100 from ETO in both season of study, while the highest values of proline and peroxidase activity were recorded with 60% from ETO. All foliar applications treatments significantly increased vegetative growth traits, leaf mineral and pigments content compared to control (without foliar spray) which recorded the highest values of proline content and peroxidase activity. Foliar application of chitosan at 500 ppm was the most effective treatment on all aforementioned parameters followed with SA at 100 ppm. Concerning the interaction effect among water irrigation levels and foliar application treatments, the best result of all studied parameters were recorded when plants irrigated with 80% from ETO and sprayed with chitosan at 500 ppm. Therefore, this treatment could be recommended to increase tomato plant growth and improve its performance.