jats:titleAbstract</jats:title>jats:pResearch on international technology transfer and partnership agreements provides a comprehensive understanding of country‐level impacts of intellectual property (IP) rights on sustainability transitions. However, firm‐level studies on how firms use and share their IP to support sustainability practices remains limited. The paper disentangles the relationship between firm‐level IP models and sustainability practices drawing from a cross‐case analysis of 28 firms offering sustainable innovations across four sectors. Analysis of firms' year‐wise data collected from 854 documents (typically 1996–2021) and 58 in‐depth interviews exploring linkage between IP models and sustainability practices of firms engaged in sustainable innovation provide six key findings: (a) emphasis on safeguarding registered and unregistered IP assets among firms with sustainable innovations; (b) widespread adoption of selectively open inbound IP models coupled with diverse IP sharing mechanisms; (c) a preference for collaborative (joint) IP ownership among internally driven firms, contrasting with a tendency for exclusive in‐licensing among those reacting to external pressures; (d) a divergence in outbound IP models, with internally motivated firms favouring selectively open approaches and externally driven firms favouring closed IP models; (e) the adoption of fully open outbound IP models democratize sustainable innovation diffusion; and (f) leveraging broadly open outbound IP models alongside closed or selectively open models balances widespread use with access control and achieves significant social sustainability. A framework is hence developed to guide technology‐sharing policies and procedures. Therefore, the paper creates a platform for prescribing sustainable IP incentives for encouraging firms to share IP for wider diffusion of sustainable innovations.</jats:p>