Salinity stress affects morpho-physiological and biochemical traits of plants. The transgenic Bt plants play a significant role in pest control, but their response and ability to cope with environmental stresses still need to be evaluated. Therefore, effect of salinity stress at 0, 50, 100, 150, and 200 mM on morphological, physiological, and molecular traits of T3 transgenic tomato plants containing cry1Ab gene (CH-Falat-Bt) was investigated and compared with that of the non-transgenic control (CH-Falat). Evaluation of the morphological traits (leaf area, root length, fresh and dry weight of roots) at different salinity levels revealed that CH-Falat-Bt transgenic plants are more tolerant to salinity stress compared to CH-Falat non-transgenic plants. The chlorophyll content at 150 and 200 mM salinity levels was 12 and 9% plants, respectively. Moreover, the amount of RWC, carotenoids, proline and soluble sugars increased significantly in transgenic plants as salinity levels increased. The relative expression of SOS1 and SOS2 genes showed a significant increase in all salinity levels in CH-Falat-Bt transgenic plants compared to CH-Falat non-transgenic plants. The amount of electrolyte leakage in the transgenic plants was significantly reduced compared to the non-transgenic plants. The results of morphological, physiological, and molecular investigations of CH-Falat-Bt transgenic plants confirmed that the undesirable effects of salinity stress on transgenic plants is much less than non-transgenic ones. in general CH-Falat-Bt transgenic plants are more tolerant to different applied salinity levels than the wild variety.