Data on school health policy implementation are limited due to the absence of a validated measurement tool. The purpose of this study was to create and pilot a school health policy implementation survey. A modified, four-round Delphi process was used to achieve consensus on content and format of the survey. The final 76-item survey was piloted in 655 schools with a return rate of 57.1% (n = 378). Seven schools participated in environmental audits. Based on the audits, survey responses represented an accurate description of school practices for 84.2% (n = 64) of questions. The remaining 15.8% (n = 12) of survey items were eliminated or revised. This measurement tool begins to fill the research gap between the evaluation of written school health policy and implementation. Further, this tool may be used by school nurses in alignment with the Framework for 21st Century School Nursing Practice.