This study investigates the impact of biochar addition on the morphological and physiological characteristics, yield, and water use efficiency (WUE) of tomato plants (Solanum lycopersicum) under drought and salinity stress. The research was conducted in a greenhouse in Bahawalpur, Pakistan, using a three-factorial split-split-plot design with three variables: water quality (freshwater and saline water with electrical conductivities of 0.9 and 2.4 dS m⁻¹), irrigation levels (40%, 60%, 80%, and 100% of total evapotranspiration), and biochar application (3% by weight, w/w, or control). The results showed that drought and salinity stress significantly reduced plant growth parameters, leaf gas exchange attributes, and yield, while biochar application enhanced these characteristics. Biochar addition improved vegetative growth, physiological traits, water use efficiency, and reduced proline levels. Tomato yield increased by 4%, 16%, 8%, and 3% under different irrigation levels compared to the control. The study concluded that adding 3% biochar with freshwater can enhance morpho-physiological characteristics, support tomato plant development, and improve yield with higher WUE in semi-arid and arid areas. Biochar improves soil properties, enhances water retention, reduces osmotic and oxidative stress, and promotes plant growth. The study also found that biochar application significantly increased photosynthetic pigments, chlorophyll content, and water use efficiency. However, when biochar was applied with saline water under extreme stress conditions, it resulted in a 42% decrease in tomato yield. Overall, the use of biochar in sandy soils under drought and salinity conditions can enhance tomato growth and production without interaction between the two factors. The study highlights the importance of biochar in improving water use efficiency and crop productivity under abiotic stress conditions.This study investigates the impact of biochar addition on the morphological and physiological characteristics, yield, and water use efficiency (WUE) of tomato plants (Solanum lycopersicum) under drought and salinity stress. The research was conducted in a greenhouse in Bahawalpur, Pakistan, using a three-factorial split-split-plot design with three variables: water quality (freshwater and saline water with electrical conductivities of 0.9 and 2.4 dS m⁻¹), irrigation levels (40%, 60%, 80%, and 100% of total evapotranspiration), and biochar application (3% by weight, w/w, or control). The results showed that drought and salinity stress significantly reduced plant growth parameters, leaf gas exchange attributes, and yield, while biochar application enhanced these characteristics. Biochar addition improved vegetative growth, physiological traits, water use efficiency, and reduced proline levels. Tomato yield increased by 4%, 16%, 8%, and 3% under different irrigation levels compared to the control. The study concluded that adding 3% biochar with freshwater can enhance morpho-physiological characteristics, support tomato plant development, and improve yield with higher WUE in semi-arid and arid areas. Biochar improves soil properties, enhances water retention, reduces osmotic and oxidative stress, and promotes plant growth. The study also found that biochar application significantly increased photosynthetic pigments, chlorophyll content, and water use efficiency. However, when biochar was applied with saline water under extreme stress conditions, it resulted in a 42% decrease in tomato yield. Overall, the use of biochar in sandy soils under drought and salinity conditions can enhance tomato growth and production without interaction between the two factors. The study highlights the importance of biochar in improving water use efficiency and crop productivity under abiotic stress conditions.