This longitudinal study builds on research addressing changes in achievement goal orientations (AG) across the transition to middle school. We had two objectives. The first was to identify and describe different development trajectories of AG (mastery, performance-approach, and performance-avoidance) from the last year of elementary school (Grade 6) to the third year of middle school (Grade 9, or Secondary 3). The second was to determine whether these trajectories depend on individual dispositions such as anxiety, depression, aggressiveness, and inattention. A sample of 378 French-speaking students from the province of Quebec and their mothers participated in a 4-year longitudinal study. Results showed three trajectories for mastery goals (High, Moderate, and Moderate-declining) and four trajectories for performance-approach (High, Moderate-declining, Low-increasing, and Low) and performance-avoidance goals (High, High-declining, Moderate, and Low-declining). Individual dispositions in the sixth grade predicted trajectory group membership. Results are discussed in light of their implications for the literature on AG and education.