Background, objective and hypothesesDuring emerging adulthood, vocational indecision (i.e., the inability to make coherent career choices) develops in a heterogeneous fashion, with three distinct patterns: low; decreasing (i.e., developmental or adaptative); high and stable or increasing (i.e., chronic or maladaptive). Among the determinants of vocational indecision that have been identified in past research, academic motivation is a crucial an excellent choice, since it is at school that students' vocational choices are validated or not. According to SDT, this motivation can vary both in quantity and quality, and students tend to experience more positive academic outcomes when their motivational profile is optimal (high quantity, high quality) as opposed to suboptimal (e.g., low quantity, low quality). Thus, the purpose of this longitudinal study was to verify if the patterns found with emerging adulthood students characterized vocational indecision in adolescent students, and if supported, to predict the belonging to the most problematic trajectory by using students’ academic motivational profiles. We expected several distinct trajectories of vocational indecision that would differ in shape and magnitude, and several motivational profiles that vary in quality as well as in quantity. We also expected students in high-quality or quantity motivational profiles to be less likely to follow a chronic indecision trajectory.Method and resultsUsing data from 384 students (56% female; Mage = 13.52 years; SD = .52 at Secondary 2) surveyed annually from Secondary 2 to 5, person-centered analyses enabled estimation of motivational profile in Secondary 2 and vocational indecision trajectories during the 4-year period. Results revealed four distinct patterns of vocational indecision during adolescence labelled Low and Stable, Moderate and Stable, Developmental and Chronic Intermittent. Four motivational profiles were also identified in Secondary 2, ranging from poor (Highly Amotivated) to moderate (Autonomous-Introjected) quality of self-determination level. Also, in reference to the most self-determined profile, students in the Mixed profile were at greatest risk of following Chronically-Intermittently Undecided trajectory. Finally, the most self-determined students were at greatest probability of following the Developmentally Undecided trajectory.ConclusionOverall, the findings suggest that the student motivational functioning in early secondary school years could be used to identify students at risk of experiencing the negative indecision patterns across secondary school. Several theoretical and practical implications are suggested.