This manual reports on the development and validation of the original Social Emotional Health Survey-Secondary (carried out between 2012 and 2017). We shared the first version of the SEHS-S because it had sufficient validation evidence based on research completed by 2015; hence, the form reported on in this manual is called the SEHS-S (2015) version. We want to convey to our colleagues that the original SEHS-S (2015) version has an impressive body of evidence supporting it core psychometric properties, structural validity, criterion, and predictive validity (see: www.covitalityucsb.info/research.html for a list of research studies). The SEHS-S (2015) has been used in scores of research projects and by schools in 13 U.S. states to support universal monitoring of students' complete mental wellness. Hence, the SEHS-S (2015) can be used with confidence for research and applied program continuity purposes.