This paper makes a theoretical contribution by exploring the integration of sustainability principles into project management. It compares two recent methodologies, PM² and PRiSMTM, and provides a practical contribution by advocating for the adoption of these sustainability-driven practices among practitioners. Sustainability remains relatively unknown in the realm of project management, and this research aims to bridge that gap. The study follows an interpretivist philosophy and employs a combination of interviews and archival data analysis. PM², created by the European Commission, provides a project management methodology free to organizations and includes best practices from other bodies of knowledge. However, it doesn't include sustainability, because it aims to be generic. PRiSMTM, based on the P5™, aims to make the project management process more sustainable. PRiSMTM has P5 Impact Analysis and Sustainability Management Plan as the main differentiating deliverables and is an extension of the Triple Bottom Line, also including product and process. The PM² Alliance CEO believes that PM² aims to be generic, so a focus on sustainability would remove the methodology's "elasticity". However, users wishing to use PM² and consider sustainability can include it in the additional objectives and use PRiSMTM differentiating deliverables.