The National Center for Education Statistics (NCES) sponsors the National Teacher and Principal Survey (NTPS) on behalf of the U.S. Department of Education in order to collect data on public and private elementary and secondary schools in the United States. The NTPS is a large-scale, nationally representative sample survey of K-12 public and private schools and the principals/administrators and teachers who staff them in the United States. The NTPS replaced the Schools and Staffing Survey (SASS) in 2015, which had historically collected the information necessary to form a complete picture of elementary and secondary education in the United States. The NTPS has a different structure and sample from previous administrations of SASS; however, it maintains the same focus on schools and their teachers and administrators that was traditionally held by the SASS. Like SASS, the NTPS provides a wide range of opportunities for analysis and reporting on elementary and secondary educational issues. The 2017-18 NTPS consisted of three questionnaires for three target population: a school questionnaire, a principal questionnaire, and a teacher questionnaire. This Documentation report provides information about all phases of the NTPS, from survey questionnaire revisions to survey data collection and all phases of data processing.