While prior ecolabel research suggests that consumers’ trust of ecolabel sponsors is associated with their purchase of ecolabeled products, we know little about how third-party certification might relate to consumer purchases when trust varies. Drawing on cognitive theory and a stratified random sample of more than 1200 consumers, we assess how third-party certification relates to consumers’ use of ecolabels across different program sponsors. We find that consumers’ trust of government and environmental NGOs to provide credible environmental information encourages consumers’ use of ecolabels sponsored by these entities, and consumers do not differentiate between certified versus uncertified ecolabels in the presence of trust. By contrast, consumers’ distrust of private business to provide credible environmental information discourages their use of business association-sponsored ecolabels. However, these ecolabels may be able to overcome consumer distrust if their sponsors certify the ecolabels using third-party auditors. These findings are important to sponsors who wish develop ecolabels that are more credible to consumers, and thus encourage more widespread ecolabel use.