There is an urgent need for sustained funding and coordinated global efforts to strengthen health security capacities and prevent future pandemics. Writing in the Journal of the American Medical Association, experts from Resolve to Save Lives analyze critical lessons from the COVID-19 pandemic, highlighting gaps in preparedness that led to millions of deaths, economic losses, and educational setbacks. We stress the importance of building core capacities—prevention, detection, and response—at local, national, and global levels, with particular attention to low-resource settings. We advocate for sustained investment over the next 5-10 years to address these health security gaps, emphasizing that effective global collaboration is the key to preventing future pandemics.