Background: In the context of increasing healthcare demand and rising costs, and in the absence of substantial increases in financing for health, disinvestment from comparatively less cost-effective interventions has been proposed as a way to optimise health outcomes within available resources. However, explicit disinvestment rarely happens in practice despite the fact that evidence-based priority setting has garnered increasing attention in low- and middle-income countries. The aim of this dissertation is to explore economic evidence requirements and uses, policy processes and potential consequences of disinvestment in healthcare in the context of priority setting. Methods: This study is composed of three broad analytical sections: (1) a cost-effectiveness analysis of an incremental disinvestment decision (discontinuation of cotrimoxazole preventive therapy in Uganda), (2) an analysis tracking investment and disinvestment in the context of health sector-wide priority setting (health benefit package, or HBP, design in Pakistan), including a cost analysis of interventions across the health system and a study on the prioritisation of decision criteria and intervention characteristics by decisionmakers at different stages of the processes, and (3) the formulation of an explicit disinvestment model to design reduced HBPs during times of health system shocks, accompanied with a dataset of costs of care and treatment for COVID-19 in low- and middle-income countries. Results: Standard economic evaluation approaches were successfully applied to an incremental disinvestment decision in Uganda. However, inappropriate communication once the disinvestment decision was implemented created disquiet. HBP design processes can offer transparent and explicit ways of making decisions on investment and disinvestment. Rapid costing methods can be effectively used in system-wide priority setting exercises. However, uptake of cost-effectiveness evidence is not necessarily uniform across stakeholders involved in HBP design. An aversion to disinvest, even from interventions that produce low value for money, was observed but the reasons remain unclear. Shocks to the health system, such as those observed worldwide during the COVID-19 pandemic may result in intervention displacement. Without explicit evidence-based approaches to disinvestment, intervention displacement can lead to sub-optimal and inequitable outcomes. Quantitative data on intervention feasibility and urgency may improve decision-making and shine light on decisionmaker preferences. Conclusion: High quality economic evidence can be instrumental for successful decision-making in disinvestment. Data from HBP design processes can be leveraged pragmatically to aid decisionmakers in making explicit disinvestment decisions in situations of health-system shocks such as pandemics.