Sustainability is aimed at addressing the environmental and socio-economic issues of this generation and future ones. In this context, sustainable public procurement (SPP) has been proposed to link the consumption side (government) to the production side (companies), whilst addressing the four dimensions of sustainability (economic, environmental, social, and time). This paper undertakes an analysis, through hermeneutics, of four sets of system elements of SPP: (1) demand-offering, which includes products, services, and their combination; (2) procurement specifications (technical, non-technical, and socio-cultural); (3) stakeholder interactions; and, (4) research disciplinary approaches. The analysis shows that despite most SPP efforts focussing on demand-offerings or specifications, there have been some framework proposals aimed at explaining the complexities and interactions between the system elements. Additionally, most research on SPP has been carried out through single disciplinary approaches. The paper proposes the Harmonic SPP framework, which integrates the demand-offering, specifications, stakeholder interactions, disciplinary approaches, and the four sustainability dimensions, where the harmonisation of their interrelations is sine qua non. The Harmonic SPP framework is aimed at providing a more holistic perspective to SPP and thus fostering more effective and efficient SPP research and implementation.