Expanded learning time (ELT) refers to a longer school day, week, or year. ELT schools are becoming common in the United States and aim to provide all students with additional opportunities for learning, recreation, and enrichment. ELT schools differ from afterschool programs that take place immediately following the regular school day and serve a select group of students. Research on ELT schools has tended to focus on academic outcomes. This study examines whether extended school time relates to norm-breaking (e.g., cheating) and antisocial behavior (e.g., violence). A nationally representative sample of 496 schools from the 2007 Trends in International Mathematics and Science Study (TIMSS) data was used and involved students in Grades 4 and 8. Results showed a longer school day predicted high norm-breaking behavior for 4th-graders. For 8th-graders, a longer school year predicted high norm-breaking and antisocial behaviors. Results underscore studying social outcomes to evaluate ELT schools.