The composition of Greek yogurt acid whey (GYW) is considerably different from that of cheese whey making it difficult to process into powder ingredients. The high lactic acid and mineral content in GYW delays lactose crystallization, which causes stickiness during spray drying and caking during storage of the powder. Previous researches have shown that soluble soybean polysaccharide (SSPS) can enhance lactose crystallization in aqueous lactose solutions as well in concentrated permeate. However, the effect of SSPS on the crystallization of lactose in concentrated GYW has not been evaluated. The objective of this study was to determine the feasibility of using SSPS to improve lactose crystallinity and drying characteristics of GYW powder. GYW obtained from a Greek yogurt was vacuum concentrated to 56% total solids (30% Lactose) and crystallized using a laboratory-scale crystallization tank. During crystallization, the concentrated GYW at 70°C was fast cooled to 30°C followed by slow cooling to 18°C (rate, −0.05°C /min) under constant stirring. Both the control and treatment solutions were seeded with lactose crystals (0.027g/100g of solution) and 0.1% SSPS was added to the treatment solution. After crystallization the concentrate was spray dried using a pilot scale NIRO dryer. GYW powder yield with 0.1% SSPS addition was observed to be less sticky on the dryer surface. The crystallized lactose content in treatment (77.46%) was also significantly higher than control (66.56%). The hygroscopicity at 43% relative humidity and caking properties of treated GYW powder (14.4%) were significantly (P < 0.05) better than the control (12.4%). However, the glass transition temperature of the control (46.2°C) and treatment (51.1°C) powders were not significantly different (P > 0.05). The findings of this study indicate that SSPS can enhance lactose crystallization in concentrated GYW during crystallization, reduce the sticking of the powder in the dryer and improve the drying characteristics such as hygroscopicity and caking of the GYW powder.