Purpose
Inter-organisational collaboration is becoming increasingly important in complex projects; some project customers even formally require evidence of collaborative competence from potential providers. The purpose of this paper is to explore the governance of collaboration and the ways in which it is enacted in practice for complex projects.

Design/methodology/approach
The study is based on a qualitative analysis of 29 semi-structured interviews, primary data from meetings and events supported by secondary data, including standards and industry-specific contract templates.

Findings
The paper identifies how collaboration can be effectively governed in complex projects through the emerging role of the collaboration standard and its impact on contractual and relational governance mechanisms. The standard sets higher-level institutional guidelines that affect the way in which collaboration is governed in complex projects. It helps formalise informal relational practices whilst also providing guidelines for building flexibility in contracts by including coordination- and adaptation-oriented provisions conducive to collaboration.

Originality/value
The paper demonstrates the emerging role of the collaboration standard and its influence on contractual and relational mechanisms deployed in complex projects. It shows how the standard can formalise and codify informal collaborative practices and help transfer related learning across projects, thereby contributing towards the dual requirement for standardisation and flexibility in project settings.