The Devereux Student Strengths Assessment (DESSA) and the DESSA-Mini are intended to be psychometrically sound and practical measures of social-emotional competence for use in school and out-of-school-time (OST) settings. These strength-based behavior rating scales yield a variety of information designed to support the large scale implementation of social and emotional learning programs. This paper discusses 1) the context for the development of measures, 2) the choice to use a nationally-normed, adultcompleted behavior rating scale as the format for assessing student social-emotional competence, 3) the psychometric properties of the DESSA and the DESSA-Mini, 4) some challenges to assessing social-emotional competence in applied settings, 5) examples of how the DESSA and DESSA-Mini results have been used to inform practice decisions, and 6) future research and development needs for social-emotional assessment.The Devereux Student Strengths Assessment (DESSA; LeBu ff e, Shapiro, & Naglieri, 2009/2014 Comprehensive System was developed to meet the burgeoning need for a psychometrically sound yet practical measure of social-emotional competence in both school and out-of-school-time (OST) settings. The system has a number of integrated components designed to support large scale implementation of social and emotional learning (SEL). These components are described as comprehensive because they comprise screening, formative, interim, and summative assessment approaches, and as a system because these parts are interconnected through a series of procedures and principles that organize their use. Although the system can be implemented in various ways to meet local requirements, in standard practice it begins with a very brief, teacher-completed universal screening tool of student social-emotional competence called the DESSA-Mini (Naglieri, LeBuffe, & Shapiro, 2011/2014. Students who could benefit from more information are initially or subsequently assessed with the full DESSA (LeBuffe et al., 2009(LeBuffe et al., /2014).Completed by parents or teachers/staff, the DESSA can be used to formatively assess a student's strengths and needs for further instruction within eight social-emotional domains. This can inform planning decisions, such as the adoption of SEL-enhancing interventions in the form of well-known SEL curricula or more micro-strategies for building competence. Some social-emotional learning strategies, organized into a multitiered system of supports (MTSS) framework (including universal, small-group, individual, and home-based strategies), are found at an online site called Evo Social/Emotional Learning (Evo SEL). The final components of the DESSA Comprehensive System are a means of tracking progress in the acquisition of social-emotional competence using a response to intervention (RTI) framework through multiple brief forms, and a pretest-posttest comparison technique that enables users to evaluate change over time. These results can then be aggregated at the classroom, grade, school, program, or...