Fair and equitable benefit-sharing is emerging in various areas of international environmental law (biodiversity, oceans, climate change, water, food and agriculture), as well as in international processes on human rights and corporate accountability. Benefit-sharing seeks to fairly and equitably allocate economic as well as socio-cultural and environmental advantages arising from the conservation and sustainable use of natural resources, or from their regulation, among different stakeholders. Notwithstanding mounting evidence that benefit-sharing is emerging in different areas of international law, varying understandings of the concept are articulated and no systematic study discusses its evolution and diffusion. This paper proposes norm diffusion as a lens for understanding how fair and equitable benefitsharing is articulated in different sites, and discusses mechanisms, frames and actors in an interdisciplinary perspective by drawing on literature from sociology, international relations and law. A model for mapping norm diffusion in a dynamic way, considering whether actors, mechanisms and paths are active or passive, formal or informal, top-down, bottom-up or horizontal is proposed. Framing is discussed as crucial to understanding the content and embeddedness of a norm. The article uncovers underlying similarities in work on norm diffusion across the disciplines considered, and reflects on the value of an interdisciplinary approach that encourages legal scholars to consider the implications of power structures in the diffusion of law, while the nuances of legal knowledge may lead other social scientists to revisit accepted findings on norm diffusion. An in-depth understanding of how benefitsharing is diffusing is argued to be an indispensible step before an informed assessment of its potential to promote the protection and sustainable use of natural resources in a fair and equitable manner in the face of power asymmetries.