Soil salinity has become a chronic problem and a major challenge facing agricultural producers. The current study investigated the effects of the exogenous application of GB on squash plants' vegetative growth and pigment content under salt stress. Salt treatments were applied using four doses of NaCl (0 control, 1000, 2000, and 3000 ppm). 15 days after sowing, foliar sprays of GB treatments (0 mM control, 25 mM, and 50 mM) were applied. The experimental design was completely randomized using 12 treatments (4 salt concentrations × 3 foliar treatments of GB) with 5 replicates. GB enhanced growth characteristics of squash plants (fresh and dry weights, shoot length, stem diameter, leaf area, and the number of leaves), which obviously decreased when the plants were exposed to different salt stress levels. Except for the leaf area of the studied plants, which was demonstrated to be enhanced at 50 mM in this study, 25 mM GB treatment was the most effective in enhancing vegetative growth. On the other hand, GB treatments enhanced the production of photosynthetic pigments. Either 25- or 50-mM GB application significantly improved chlorophyll and carotenoid contents of squash leaves grown under salinity stress conditions compared to stress-free plants, with the exogenous application of 50 mM GB being the most effective in this investigation. The results obtained from this research clearly show that foliar applications of GB may partially or totally mitigate the harmful impacts of NaCl salt stress on vegetative growth and photosynthetic pigments.