This study investigates the relationship between eco-certifications (second or third party certified with an audit requirement) and resource efficiency in the U.S. hotel industry. Hotel properties become eco-certified by voluntarily conforming to environmental practice guidelines established by a certifying body, which assesses and recognizes the properties that meet their criteria. Eco-certifications therefore are key environmental sustainability initiatives that address both the internal operations and external customers. Based on regression analysis of 2,893 U.S. hotel properties for the year 2011, this analysis shows that eco-certified hotels maintain higher operational efficiency, as well as greater customer-driven resource efficiency, in comparison with properties with lesser or no eco-certifications. These results suggest that eco-certifications influence the resource consumption behavior of both the operators and the customers, although these effects are not consistent for all properties. The improvement from the operational effect is most pronounced in lower-tier properties, while the customer efficiency effect is most noticeable in upper-tier properties.