This purpose of this resource is to support state and local education agencies in identifying reliable and valid instruments that measure collaboration, perseverance, and self-regulated learning among secondary school students. This resource, developed by the Regional Education Laboratory Northeast & Islands in collaboration with its Social and Emotional Learning Alliance, presents social and emotional learning instruments and the reliability and validity information available for those instruments. Specifically, this resource indicates whether psychometric information was available for reliability and seven components of validity--content, substantive, structural, external, generalizability, consequential, and fairness. To identify and review instruments, researchers conducted a literature search, determined the eligibility of instruments, reviewed the reliability and validity information available for eligible instruments; and determined whether the reliability and validity information provided met conventionally accepted criteria. In total, 17 instruments were eligible for inclusion in the resource. Eligible instruments included six measures of collaboration, four measures of perseverance, four measures of self-regulated learning, and three measures of both perseverance and self-regulated learning. With 12 instruments developed for use in research and 5 instruments developed for formative instruction, practitioners should use caution when using any measure for summative use that has not been developed and validated for that specific purpose. With schools and districts ramping up their efforts to measure social and emotional learning for formative and summative use, practitioners would benefit from the development of additional measures for these specific purposes. Among the 17 instruments eligible for inclusion in this resource, 16 instruments have information on reliability and at least one component of validity. The component of validity most commonly available for eligible instruments was content validity whereas only three instruments had information on fairness and no instruments had information on substantive validity. Practitioners should use caution when using instruments that lack information on substantive validity or fairness, since these measures may not be appropriate for all students that are evaluated.