The HVDC industry is moving towards multivendor HVDC systems, with multiterminal systems under planning in many parts of the world, and the desire for DC-side system expansion included in many functional requirements. Today’s typical collaborative design methods are not suitable to meet the challenges of these future multivendor systems, which will increasingly require sharing of information about elements of the system (e.g., converter control, protection, …) as well as interdisciplinary decision-making on coordination of devices and the overall system functionality. One method to enable more effective system development in such an environment is Systems Engineering or Model-Based Systems Engineering (MBSE). There are numerous ways in which to use Systems Engineering to enable HVDC system specification, design, and implementation according to the needs of the application. This paper discusses the possible future needs of HVDC systems, and considers different ways in which Systems Engineering can be used to perform more effective specification and design in a multivendor context. The work is one outcome of CIGRE WG B4.85 (‘Interoperability in HVDC systems based on partially open-source software’). The use of MBSE in existing HVDC systems is first discussed, identifying that some manufacturers use Systems Engineering tools extensively for HVDC project design and development, but there is currently no framework or method for sharing models externally. Several case studies are then examined, discussing possible methodologies and benefits of using Systems Engineering for grid-level design, converter control definition, functional division, and grid-level control and protection definition. The high-level challenges and outlook for future widespread application of MBSE are then discussed, highlighting the need for additional technical harmonisation in the field as well as more efforts towards collaboration mechanisms to enable sharing of information that is becoming essential for effective multivendor system design and expansion.