Promotion and online reviews — have been considerably studied separately. Although marketing literature has shown that promotions could influence customer postpurchase evaluative response, little is known about how promotions will affect customer behavior in online reviews. This research examines the effects of promotion on online review ratings. In addition, this study also explores how temporal distance between purchase and posting online review, and customer deal proneness moderate the relationship between promotion and online review ratings. We collect a unique dataset by combining customer transaction records with their behavior in online reviews, and use an ordered probit model to test our hypotheses. Our results show that coupon promotions have a positive impact on online review ratings, and the strength of this impact varies in reverse of the time delay between purchase and posting online reviews. And this relationship is enhanced when customers have high deal proneness.