In today’s world, sustainability is reshaping the business paradigm projects are contributing to. And project managers need to be ready for this in order to deliver successful projects. The development towards sustainability requires a 'systems change' that impacts organizations at all levels. As projects shape the future, they play an instrumental role in realizing these changes. In this context, the traditional task-oriented nature of project management, with a narrow focus on delivering the agreed project output, does not suffice anymore. Managing projects in organizations with increasing ESG commitments requires an alignment of projects with the sustainability strategy, goals and standards of the sponsoring and participating organizations, that goes beyond the traditional scope of consideration of project management. As project management evolves in this context of ESG commitments towards Sustainable Project Management, so will project managers need to do. It is not anymore about “green” projects, or about considering “green” in project management: Sustainable project management represents a scope, paradigm and mind shift in project management, and requires specific competences of project professionals. This Reference Guide provides the integration of sustainability competences into the competence baseline defined in IPMA ICB4. The guide identifies 92 Key Competence Indicators that are crucial for project professionals to succeed in projects, today and tomorrow.