The COVID-19 pandemic has demonstrated that: 1) there is no single ‘cookie-cutter approach’ to health systems strengthening, and 2) health systems must be significantly more holistic and equitable. This chapter examines the global spread of COVID-19 and its impacts on health systems and communities. By analysing public health gaps and challenges in L&MICs, the authors provide concrete examples of innovations and interventions that were effective in responding to the pandemic. It explores how different health systems across L&MICs and HICs can be better equipped to mitigate health emergencies and maintain routine health services by leveraging a range of essential public health functions, primary health care, and risk management capacities. Health systems resilience is only possible when systems thinking is operationalized and aligned with the wider SDGs. There is a case for multisectoral engagement in mounting a comprehensive health systems response to COVID-19 at the national and global levels. The chapter offers lessons on why strengthening health systems -- through integrated investments and with equity and resilience as key objectives – is key to sustainably achieving health security and universal health coverage.