This ISPE Sustainability Guide is a foundational document that presents key principles and concepts to reinforce sustainable practices in the pharmaceutical industry, based on global and local guides, including existing regulations. Although intended for Small and Medium Sized Entreprises (SME) at the start of their sustainability journey, larger organizations may also use this Guide to support their sustainability strategy. The main objectives of the Guide are to provide an overview of key environmental sustainability definitions, to develop a cohesive industry approach that integrates sustainability into existing pharmaceutical development, operations, quality and supply chain processes, and to provide guidance on the management of sustainability programs, including the use of metrics to measure performance. Key concepts discussed include: Product and Environmental Sustainability Net-Zero (Greenhouse Gas Emissions) Nature Positive Sustainability by Design Circular Economy Ethical Considerations The intent is to guide the pharmaceutical industry toward a future where sustainable practices are embedded in every lifecycle stage of pharmaceutical development and production.