A pots experiment was conducted to assess the stress effects of salinity and water deficit on Lagerstroemia indica L. Salinity stress was imposed by irrigating with saline water at concentrations of 500, 1000, 2000, or 3000 ppm, in addition to the control (tap water of 280 ppm). Whereas water deficit was applied by using tap water for irrigation at intervals of 4, 6, 8, or 10 days. The treatments were arranged in a split-plot design, with the salinity treatments assigned to the main plots and the water deficit treatments assigned to the subplots. The results indicated that vegetative growth and flowering parameters (plant height, number of leaves/plant, number of branches/plant, stem diameter, root length, dry weight of shoots, number of flowers/plant and flower diameter), as well as total chlorophylls, total carbohydrates, N, P, K⁺ and Ca²⁺ % were reduced in response to both salinity and water deficit stresses. In contrast, both stresses resulted in an increase in the concentrations of Na⁺, Cl⁻, proline, total phenolics and antioxidant enzymes activities (CAT, SOD and APX) in leaves. The interaction effects showed that in plants irrigated every 6 or 8 days with tap water or every 4 days using a salt concentration of 1000 or 2000 ppm, the reduction in growth and flowering parameters, total chlorophylls, total carbohydrates, N, P, K⁺, and Ca²⁺ % was insignificant. Compared to unstressed plants, the accumulation of harmful Na⁺ and Cl^- ions was insignificant in plants that were irrigated every 6 or 8 days with tap water or every 4 days with salinity levels up to 2000 ppm. Based on the findings of this study, it can be concluded that L. indica can be irrigated every eight days with tap water or every four days with saline water with concentrations up to 2000 ppm without any significant reduction in most of its vegetative growth and flowering characteristics.