Nearly 70 participants of the flagship working group have been drafting and validating the “Guidance on Organizational Life Cycle Assessment” over the past two years. The long-awaited publication is now available for download. The authors expect the guidance document to support a broader application of organizational LCA. Organizational life cycle assessment (O-LCA) uses a life cycle perspective to compile and evaluate the inputs, outputs and potential environmental impacts of the activities associated with the provision of an organization’s product portfolio. O-LCA includes not only the facilities of the organization but also upstream and downstream activities. This methodology is capable of serving multiple goals at the same time, like identifying environmental hotspots throughout the value chain, tracking environmental performance over time, supporting strategic decisions, and informing corporate sustainability reporting. The first tentative steps toward full O-LCA application are currently taking place, and the outcomes of these are already being used to improve organizations’ environmental performance. Broadening the base of implementation is the logical next step, requiring accessible, practical guidelines and guidance. This publication provides an overview and the needed guidance to support the application of O-LCA, with special focus on its main methodological challenges. It is targeted to practitioners, decision makers, methodology developers, consumers and other stakeholders. O-LCA is envisioned for organizations of all sizes, both public and private, in all sectors, and all over the world. We devoted special efforts to make the new methodology operative for all of them. Furthermore, the guidance document defines the so-called “experience-based implementation pathways” and provides particular methodological support according to previous experience of the organization with other environmental tools. Eleven experiences of the so-called “First Movers” of O-LCA illustrate the process and benefits that the methodology could bring to organizations. Eight sectors and four regions are represented in the case studies.