This study examines the degree of association between students' STEM occupational expectations and between-country differences in public attitudes toward science and technology (S&T). This study focuses on public attitudes among two different populations: students and adults. Three-level Hierarchical Generalised Linear Models are employed to analyse large-scale international data from the Programme for International Student Assessment (PISA). Results reveal that public attitudes toward S&T are positively associated with students' expectations around pursuing STEM careers. Further analyses reveal that the positive association between public attitudes toward S&T and STEM career expectations remains consistent across gender, but that this association varies across performance levels. The positive association between public attitudes toward S&T and STEM career expectations is stronger for low achievers in science than for high achievers. These results advance the scholarly understanding of the ways in which social factors may be associated with students' choices in pursuing STEM occupations.