The present study aims at unravelling the myriad of student-level (i.e., gender, socioeconomic status [SES], academic self-concept, achievement, ability, and occupational interests) and school-level (i.e., gender composition, maths composition, and SES composition) determinants of option choice in the academic track of secondary school in Flanders. We focused on 2 decisional thresholds in Flemish secondary education, namely, the transition from Grade 8 to Grade 9 (N = 2518) and from Grade 10 to Grade 11 (N = 2871). Data were analyzed through multinomial multilevel analysis. Our results strongly confirm Lent's (2005) jigsaw puzzle metaphor in that different factors go into a complex and dynamic interplay. Especially in the first grades, prior achievement is a major predictor of option choice in secondary education, whereas in the last years occupational interests become increasingly important. From a gender perspective, boys rather choose math/sciences-oriented options than girls. Option choice is mainly determined by student-level rather than school-level predictors. (Contains 5 tables and 1 figure.)