How does a vendor’s explanation to negative online consumer reviews influence consumers’ trust in the vendor? Little understanding is available in either service recovery literature or ecommerce literature. In the online environment, a vendor’s response to customer complaints is often posted on a website and examined broadly by consumers including complainants and potential consumers. This is different from the offline environment whereby of the explanation is only received by complainants. Therefore effectively response to online negative reviews is a critical business activity that is oriented towards consumers in a larger scope than it would be in the offline environment. We intend to investigate how an online vendor’s response influences consumers’ trust beliefs toward the vendor. Justice theory and Toulmin’s model of argumentation are applied to analyze the meditating variables between vendor explanation and consumer trust. Three constructs, i.e., apology provision, explanation adequacy and responder information disclosure, are proposed to be the mediating variables. For practitioners, they also serve as guidance to construct response content.