Purpose: This paper sets out a framework for planning co-design processes for complex sys-tems-based projects typical in healthcare settings. Background: Healthcare systems and environments are complex. Innovation often requires the redesign of physical spaces or objects, social processes, and the complex associated layers of ser-vice systems. Co-design is an established methodology for catalysing innovation in products and services because the scope is often well-defined but can be more challenging when working in sys-tems where complexity impacts boundary definition. Co-design uses interdisciplinary and mul-ti-level engagement with diverse stakeholders to catalyse innovation at the intersection between disciplines, experiences, and knowledge sets. The evaluation of these processes often utilises con-trol over decision-making as a defacto measure of participation quality, reflecting potential for stakeholders to influence key outcomes. Yet there are also practical and theoretical reasons to val-ue well-designed participatory processes in their own right. Methods: The framework presented in this paper combines the evaluation of participation in co-design processes and in decision-making as two distinctive activities, applied to real-world and hypothetical case studies that demonstrate the potential of this framework as a transparent plan-ning and evaluation tool. Results: The framework allows participation to be planned and valued independently without defaulting to control over decision-making processes as the (only) valued option. The case studies demonstrate its potential in structuring a range of collaborative processes that suit different types of system innovation. Conclusions: The formalisation of a framework for planning co-design activities that values participation in co-design processes in parallel with participation in decision-making provides a more transparent and beneficial way to structure co-design for complex systems-based challenges that recognises the humans at the heart of co-design.