The purpose of this work is to identify contextual variables that help to explain the occupational aspirations of Spanish 15-year-old students. This is done by performing a secondary analysis of the PISA2018 test. Data have been analysed using decision trees introducing the students' expected occupational status as a dependent variable (DV), and the other items and indicators considered as predictors. The results show that the variables that contributed most to explaining DV were grade repetition, mastery goal orientation, enjoying reading and self-concept of reading. The findings of this exploratory work can be used as a basis for further studies aimed at establishing causal relationships between these variables and students' occupational aspirations.