The Social-Emotional and Character Development Scale (SECDS) is intended as a measure of social-emotional skills and character for elementary school-age children. This study investigated the measure's psychometric properties using data collected over 5 waves for a cohort of students followed from Grades 3 to 5 in 14 urban elementary schools (N Range = 500 to 593). Confirmatory factor analysis indicated good fit to the measure's hypothesized first- and second-order factor structure at each wave. Scales corresponding to the first-order factor structure demonstrated adequate internal consistency and test-retest reliability. Consistent with previous research using similar measures of social-emotional skills and character, a longitudinal analysis indicated that the means for these scales decreased over the 5 waves. The validity of the SECDS general and individual scales was supported via their patterns of association with measures of expected correlates of social-emotional skills and character. Overall, findings suggest the SECDS is appropriate for assessing the development of different facets of social-emotional skills and character during elementary grades and that it could be useful for investigating their role in the developmental pathways for a range of important youth outcomes.