 The COVID-19 pandemic has highlighted the urgent need for increased investment in global health security. In order to ensure adequate funding, we must understand the full scope of the problem and its associated costs. This study provides a comprehensive analysis of the costs associated with strengthening health security in countries around the world. It identifies personnel costs as the primary driver of expenditure, accounting for over two-thirds of total costs. Additionally, the study found that personnel costs are the greatest barrier to achieving demonstrated capacity under the World Health Organization's Joint External Evaluation Framework. This information can be used to inform future discussions about how best to allocate resources to improve global health security. This article was authored by Stephanie Enef, Ellie Greeden, Amanda McClelland, and others.