Few Spanish language tools are available for assessing important social-emotional learning (SEL) skills. The present study presents evidence of the psychometric properties of a Spanish-language version of SELweb (SELweb-S), a web-based system for assessing children's ability to recognize others' emotions and perspectives, solve social problems, and engage in self-control. With a sample of 524 students in Grades K to 3, we examined the reliability and validity of SELweb-S. This study provided evidence that (a) individual assessment modules exhibited moderate to high internal consistency and moderate 6-month temporal stability, (b) composite assessment scores exhibited high reliability, (c) assessment module scores fit a theoretically coherent factor structure, and (d) performance on SELweb-S assessment modules was positively related to teacher-reported SEL skills. Findings are discussed in terms of the importance of direct assessments of SEL skills in languages other than English. In addition, we highlight the importance of abiding by rigorous recommendations in the literature for the translation and cultural adaptation of assessments.