An emerging body of research documents a relationship between sleep quantity and delinquency during adolescence. Absent from this line of research, however, is an evaluation of whether the associations between sleep duration and different forms of delinquency vary across periods of adolescence and sex. The current study aimed to address this gap in the body of literature by analyzing data from nationally representative samples of 8th, 10th, and 12th graders from the 2010 to 2019 Monitoring the Future (MTF) surveys. Multivariate regression models reveal that relations between getting less than 7 hours of sleep and violent and non-violent delinquent behavior vary across grade level. Specifically, associations between less sleep and forms of delinquency are stronger for males in grades 8 and 10 compared to males in grade 12 or females. Implications of the results for future research and policies designed to increase sleep quantity during adolescent development are discussed.