Purpose – The purpose of this study is to analyse collaborative product development in business relationships as a means of achieving a circular economy in business networks.

Design/methodology/approach – The theoretical framework is based on the Industrial Marketing and Purchasing approach, which views companies as part of business networks, and identifies business relationships as the key building blocks of these networks. The methodology employed is a case study of a collaborative project within the denim industry.

Findings – The results show that the development of circular products has an impact on the broader business network of the two collaborating companies. This has implications for the wider business networks of the two collaborating companies, including supplementary process development.

Practical implications – The results of the study may be of use to companies that intend to develop circular business models and contribute to a more sustainable future in resource-intensive industries.

Originality/value – This research makes a contribution to the academic discourse on circularity by offering insights into the potential of circular business models in developing circular products through business relationships.