The superfood quinoa is an extremely nutritious and ancient pseudocereal grain particularly known for its protein quality and bioactive compounds, compared to other cereals. Quinoa seeds can be processed into a crispy, cellular-structured and expanded whole-grain snack product by low capital cost involving traditional sand puffing method. The study aims to statistically optimize the processing conditions for sand puffing of quinoa. The moisture-treated and salt-treated quinoa grains were mixed with a high-temperature sand bed for a predetermined time to induce grain expansion. Puffing conditions were optimized using Box-Behnken design by varying the factors such as moisture added (0.2-1.8 ml/10 g grains), salt concentration (0-1%), puffing temperature (200-240 ºC) and puffing time (20-60 s). It was found that measured response parameters like puffing yield, expansion ratio, flake size and overall acceptability of puffed quinoa significantly (p<0.05) increased with a decrease in moisture added and salt concentration, and increase in puffing temperature and puffing time. Bulk density of puffed quinoa had a negative correlation with puffing temperature and puffing time. The optimum condition of 0.2 ml moisture added/10 g grains, 0.2% salt concentration, 229ºC puffing temperature and 55 s puffing time was predicted to generate puffing yield of 86.23%, expansion ratio of 3.08, flake size of 8.21 mm3, bulk density of 0.36 g/ml and overall acceptability score of 8.65. The higher yield, three-fold expansion and superior sensory attributes of puffed quinoa achieved from optimized sand puffing condition would benefit the manufactures and be nutritious snack food for consumers to combat malnutrition.