This document discusses the threat posed by invasive species to military bases. Through 12 case studies of Army, Navy, Air Force, and Marine Corps installations, the report finds that invasive species negatively impact military operations by degrading habitat for wildlife, hindering training activities, and increasing costs. The National Wildlife Federation hopes this report will inspire greater cooperation between the Department of Defense, natural resource managers, scientists, and others to address the problem of invasive species spreading across the United States.