Currently, public health emergency preparedness (PHEP) is not well defined. Discussions about public health preparedness often make little progress, for lack of a shared understanding of the topic. We present a concise yet comprehensive framework describing PHEP activities. The framework, which was refined for 3 years by state and local health departments, uses terms easily recognized by the public health workforce within an information flow consistent with the National Incident Management System. To assess the framework's completeness, strengths, and weaknesses, we compare it to 4 other frameworks: the RAND Corporation's PREPARE Pandemic Influenza Quality Improvement Toolkit, the National Response Framework's Public Health and Medical Services Functional Areas, the National Health Security Strategy Capabilities List, and the Centers for Disease Control and Prevention's PHEP Capabilities.