Changes in early adolescents' self-reported cheating behaviors in mathematics before and after the transition from middle school to high school are examined. Students were surveyed in school regarding their cheating behaviors in math, and the motivational goal structures perceived in their math classrooms. Surveys were completed twice during the eighth grade (during middle school) and once at the end of the ninth grade (at the end of the first year in high school). Results indicated that self-reported cheating did not change in the year prior to the high school transition, but that reported cheating increased after the transition. Additional analyses indicated that across the high school transition, self-reported cheating in math increased for students who moved from high mastery to low mastery-oriented classes after the transition, and for students who moved from low performance to high performance-oriented classes; in contrast, self-reported cheating decreased for students who moved from low to high mastery-oriented math classrooms.