["The Career Development Quarterly, EarlyView. ", "\nABSTRACT\nThis study examined the career development of Brazilian undergraduate students in science, technology, engineering, and mathematics (STEM) fields through the lens of the psychology of working theory (PWT), focusing on career barriers, volition, social support, and future decent work. The sample comprised 489 students from public institutions who were predominantly young, male, and economically dependent. Findings indicated that career barriers negatively predicted volition and future decent work, while the latter was positively associated with satisfaction with the academic major. Volition functioned as a mediator between barriers and decent work. Different sources of social support exerted specific moderating effects: family support softened the negative impact of barriers on volition, whereas support from significant others mitigated the effect of barriers on decent work. The results reinforce the applicability of the PWT to the Brazilian context and reveal that, even in fields considered promising, students experience vulnerabilities that affect their career trajectories.\n"]