Tomato (Solanum lycopersicum) imports have increased in Malaysia due to high demand. One of the constraints to local production is excessive salinity in soils that leads to toxicity in crops, reduction in soil fertility and reduction of availability of water to tomato plant that is known to be sensitive to high salinity. Nevertheless, silicon nutrient proven could protect plants from abiotic stress. Therefore, the objectives of this study were to determine the plant growth of tomato plant treated with silicon (Si) under salinity stress and to observe the physical changes of stems. A total of ten treatments (T1 – T10) were applied with different concentrations of silicon: 0.5% Si (v/v), 1.5% Si (v/v), 2.5% Si (v/v), potassium silicate as positive control whereas negative control (only water and 0.5% NaCl) and a mixture of equal volumes of the silicon and potassium silicate treatments with 0.5% NaCl. The treatments were applied once a week (40 ml for each plant pot). Throughout this study, plant growth data was collected (plant height, diameter of stems, time of anthesis, number of fruits, and chlorophyll content). Results showed that with 0.5% Si (v/v) and 1.5% Si (v/v) (with 0.5% NaCl), the tomato plants grow well especially in plant height, number of leaves and chlorophyll contents. Furthermore, cross section of stems showed a significant difference (p<0.05) in stem diameter among treated plants [2.5% potassium silicate (T4), 0.5% Si (v/v) + 0.5% NaCl (T6) and 2.5% potassium silicate + 0.5% NaCl (T9)] and control (0.5% NaCl). However, the largest vascular bundle width was recorded in plants treated with 1.5% Si (v/v). This study has proven that tomato plants could uptake silicon and improve the plant growth under salinity stress conditions and giving potential for Si as biostimulant to other Solanaceae family (potato, pepper and eggplant).