Stakeholder engagement in collaborative research and innovation projects poses significant challenges, particularly in complex, multistakeholder settings addressing sustainability concerns. This study proposes a novel method for stakeholder prioritization in such projects, combining the analytic network process (ANP) tool with the sustainability categories of the P5 standard for sustainability in project management. Its applicability and usefulness are demonstrated through a case study project, using the new stakeholder theory (NST) lens. The ANP-P5 method can assist project managers in effectively aligning stakeholder management with both sustainability and NST principles.