Emotional intelligence (EI) theory provides a framework to study the role of emotion skills in social, personal, and academic functioning. Reporting data validating the importance of EI among youth have been limited due to a dearth of measurement instruments. In two studies, the authors examined the reliability and validity of the Mayer-Salovey-Caruso Emotional Intelligence Test--Youth Version (MSCEIT-YV), a performance test of EI. Study 1 examined psychometric attributes of the MSCEIT-YV in a large sample of fifth- to eighth-grade students (N = 756). Study 2 examined the relationship of the MSCEIT to student and teacher reports of academic, social, and personal functioning among fifth- and sixth-grade students (N = 273). The authors report that EI can be measured reliably with the MSCEIT-YV and that higher scores on the test are related to healthier psychological functioning and greater social competence based on both teacher and student ratings, as well as to academic performance in English language arts. (Contains 5 tables and 2 figures.)