Students' career decision is a relevant topic in career development with scholars and practitioners aiming at understanding which factors can contribute to students decision-making to support them in their career path. In this study, we argue that facilitating conditions can positively influence the career decisions of students. This relationship is mediated by career self-efficacy and moderated by optimism. To test our hypotheses, we conducted a longitudinal study. In total, 789 high school students from different educational streams took part in our three-way study. Results showed that career decision-making self-efficacy mediates the relationship between facilitating conditions for school motivations and career decision-making. While the direct effect of facilitating conditions for school motivations on career decidedness is negative, the relationship linking facilitating conditions for school motivations to career decision-making self-efficacy, as well as that linking career decision-making self-efficacy and career decidedness, is positive. These results provide insights for better-targeting counselling programmes.