This study aimed to examine how the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) online food benefit ordering could influence WIC benefit redemptions, comparing the average redemption rates between online ordering early adopters and non-adopters among WIC customers before and after implementing WIC online ordering. A propensity score-weighted difference-in-difference model was used to estimate the coefficients. The setting was the Oklahoma WIC programme and a grocery store chain in Oklahoma. Participants were 12,743 Oklahoma WIC households that had redeemed their food benefits at the grocery store chain in 2020. WIC online ordering significantly positively affected redemption rates for eight of the fifteen food categories. For example, the difference-in-difference coefficients (P-values) of these food categories were cheese or tofu (0·077, <0·01), yogurt (0·092, <0·01), whole milk (0·082, 0·022), low-fat milk (0·060, <0·01), eggs (0·049, 0·033), breakfast cereal (0·085, <0·01) and infant formula (0·073, 0·039). Two food categories with significantly negative difference-in-difference coefficients had relatively lower redemption rates overall: canned fish (Coefficient = -0·209, P < 0·01) and infant cereal (Coefficient = -0·138, P = 0·015). There were no significant changes in the redemption of fruits and vegetables (Coefficient = 0·031, P = 0·121). Adopting WIC online ordering was positively associated with benefit redemption rates among most food benefit categories. Our findings provide preliminary but important evidence regarding online food benefit redemption among low-income consumers.