Mathematics anxiety negatively impacts cognitive processing, performance, expectations, motivation, and future choices. However, research has not examined patterns in students' mathematics anxiety levels over time. The current study addresses this gap by exploring group-based trajectories in mathematics anxiety during the transition to junior high school. Five trajectories are described: consistently low anxiety, consistently high anxiety, steady decline, summer decrease, and summer increase. Predictors of trajectory membership, including student demographics and motivational variables like self-concept, are explored. Trajectory membership predicts longitudinal differences in expectations and values after high school. Implications for research on students' mathematics anxiety over time and especially during transition are discussed.