Shopping cart abandonment (SCA) is the phenomenon whereby an online buyer places items into her virtual shopping cart but eventually chooses to abandon payment. This research examines the effect of buyers’ uncertainty perceptions on SCA behaviour, and prescribes the ways to mitigate them. Building on the e-commerce literature, we identify seller uncertainty, description uncertainty, and performance uncertainty as the key antecedents of SCA and explore their relative influences on customers’ intention to finalize the transaction. Drawing upon uncertainty reduction theory (URT) from the communication literature, we theorize critical communication capabilities and discuss their relative effectiveness and boundary conditions in reducing different types of uncertainty perceptions. Survey data were collected from 237 online shoppers who were hesitating to checkout items in their virtual shopping carts. The results provide support for our structural model and hypotheses in general, with a few interesting exceptions. We suggest a plausible explanation of these results and point out their implications for future research. Suggestions for e-commerce practices are discussed.