Crises affect schools across the country every day. While natural hazards such as tornadoes, floods, hurricanes, and earthquakes may be thought of more commonly as emergencies, schools are also at risk from other hazards such as school violence, infectious disease, and terrorist threats. Through the vulnerability assessment process, schools can take steps to prevent, mitigate, and lessen the potential impact of these risks by developing customized district and school emergency management plans in collaboration with community partners. Vulnerability assessments are integral to, rather than separate from, the ongoing emergency management activities of school districts and schools. Vulnerability assessment is the ongoing process for identifying and prioritizing risks to the individual schools and school districts. It also includes designing a system of accountability with measurable activities and timelines to address risks. As schools continue to plan and prepare for critical events that could have severe consequences, identifying the appropriate vulnerability assessment tool(s) is an important step for helping schools to understand what they are at risk from and just how seriously they could be affected. Schools need to use appropriate tools to capture the relevant data needed to inform the development and maintenance of customized plans. This guide is intended to be a companion piece to Practical Information on Crisis Planning: A Guide for Schools and Communities, originally published by the U.S. Department of Education in 2003 as a guide for schools and districts to prepare for a variety of crises. This guide emphasizes a valuable part of emergency management planning-ongoing vulnerability assessment-and is intended to assist schools with the implementation of an effective vulnerability assessment process, to include choosing an appropriate vulnerability assessment tool. Vulnerability assessment tools may vary from one school site to another, depending on variables such as: location, environment, size, and structure, and even student population and school culture. For example, schools may be located in urban or rural environments, may have limited or greater resources, or may have specific populations with their own unique needs. As a result, vulnerability assessments must be customized on an individual district and school basis, taking all of these factors into consideration. This guide is not intended to be prescriptive or to give step-by-step instructions for conducting assessments, rather it is intended to describe the key elements to be considered when selecting an assessment tool appropriate for school environments and provide guidance for conducting an assessment that will inform school emergency management activities.