AbstractThis paper utilizes novel household panel data to analyze the effect of online grocery shopping on the healthfulness of grocery purchases. We utilize variation in the timing that an online shopping service was introduced as a source of exogenous variation in the decision to shop online. Relative to pre‐online service averages, our estimates indicate that online shopping baskets allocate 10.2 (21.7)% more of the total spending (calories) toward healthful product categories and are 10.1% more nutrient dense. We also evaluate the effect of online shopping on the monthly aggregate (in‐store and online) basket. Average treatment effects for the treated (ATT) indicate a 2.3% decline in the sugar/sweet/candy budget share upon the introduction of the online shopping service; however, summary measures of healthfulness do not illustrate robust changes at the monthly level.