Suicide is the second leading cause of death for youth aged 10-24 in the USA. In response to the high rate of youth suicide, teen suicide has gained national attention and, as a result, state governments have created legislation regarding youth suicide prevention in schools. States hold the power to instruct their schools in how to address suicide prevention, but little research has explored the relationship between state laws about school-based suicide prevention and schools' actual practice of suicide prevention or about the effectiveness of different types of laws. The current study examined this relationship by surveying a nationally representative sample of high school principals. It assesses their knowledge of and compliance with state laws about suicide prevention, adherence to best practices for school-based suicide prevention, and variables that predict their schools' suicide prevention program comprehensiveness. Results indicated that only about 25% of principals (N = 656) accurately identified their states' laws about school-based suicide prevention, and 66.1% reported that their schools' suicide prevention programs are in complete compliance with their states' laws. Principals in states with the most stringent laws reported having the most comprehensive suicide prevention programs. Having funding, perceived support, student socioeconomic status, and having a student in their current school die by suicide were all significantly related to suicide prevention program comprehensiveness. Implications for policy, practice, and research are discussed.