<p>Active orthoses are gaining increasing interest, particularly those intended for lower limbs, due to their potential to enhance independence in performing Activities of Daily Living (ADLs). Nevertheless, numerous impediments to their widespread adoption persist. Among these are the necessity for an adequate production process to ensure the quality of a custom-made product in terms of functionality, geometry, and aesthetics. Additive Manufacturing (AM) emerges as a promising technology for the production of patient-specific active orthoses intended for ADLs assistance. However, a comprehensive workflow to support the effective integration of this technology is still lacking. The present work proposes a structured methodological workflow for the design of active orthoses to be produced via AM. The workflow outlines relevant guidelines and international standards, and defines the data flows, as well as the hardware and software resources required for AM-based design implementation. The methodology is validated through a theoretical case study of an active knee orthosis. This case study highlights the importance of a detailed workflow that specifies the resources needed to carry out integrated design, in order to ensure an efficient and effective design process. This methodological approach addresses all project requirements, including user comfort, functionality, and manufacturability, to create a compliant device. The workflow developed in this manner, thus, serves as a comprehensive practical guide for those interested in exploring AM as a technology for active orthosis production.</p>