Mitigation the activity of α-amylase and α-glucosidase is scientifically spotlighted to potentially decrease the glucose absorption and scavenge category 2-diabetes mellitus in the humans. For the first time, we elucidated the underlying mechanism of the inhibitory activity of 3 structurally different phytosterols (PS) on α-amylase and α-glucosidase using multispectral and molecular docking approaches. It was found that stigmasterol, β-sitosterol, and γ-oryzanol integratedly (competitive and uncompetitive) inhibited both of α-amylase and α-glucosidase. The spectrofluorometric results demonstrated that a static interaction of PS with both enzymes happened, leading to the changes in Z-average size, UV–vis spectrum, and secondary structures of these amylolytic enzymes. Moreover, each PS noncovalently interacted with several residues close to the active sites of both enzymes via H-bonding and π-π forces, causing indirectly inhibition to their catalytic activity. However, γ-oryzanol was highly inhibited both enzymes than the other PS since its structure in which contained ferulic acid esterified with sterol, which could be used as nutraceutical ingredients.