This research inquires whether sustainable voluntary private certification schemes (CS) can be effective means of advancing sustainability practices inside companies and of improving financial performance. This thesis focuses on a particular certification, namely the Brazilian Leather Certification of Sustainability (CSCB), this specific certification aims to introduce best practices in tanneries by centering on four dimensions: economic, environmental, social, and sustainability management. Twelve qualitative in-depth interviews were conducted with members of the CICB as well as with owners, directors, and employees of eleven different tanneries. Finds reveal that the certification has a positive impact on tanneries when it comes to data documentation, which allows for improvements in process and operations. Just as importantly, the CSCB helps create and foster a more sustainable culture within organizations. The financial impact of the CSCB on organizations remains statistically uncertain. This being said, findings show that financial performance can be improved in the long term as results of investments in sustainable practices.