Online consumer complaints are closely related to business reputation and elicit managers' persistent efforts. However, service providers in the sharing economy (SE) lack the skills to communicate with consumers because most are informal or nonprofessional property owners. This research aims to examine the relationship between service providers' responses and prospective consumers' perceived helpfulness in the SE by using bed and breakfasts (B&B) as the sample. Response length and voice are adopted to measure the content quality of B&B's response to an online complaint. Three types of voices (defensive, formalistic, and accommodative) are identified by analyzing service providers' responses to negative reviews, among which the accommodative voice with empathic statements is the most effective. An inverted-U curve relationship between response length and helpfulness votes is verified based on cognitive load theory. Moreover, interactive effects between response length, review length, and images are also examined. This study suggests the investigation of online reviews from comprehensive perspectives, as well as the adoption of personalized strategies by SE practitioners to respond to consumer complaints.