This conceptual contribution aims to adapt and apply Psychology of Working Theory to the specificities of the school-to-work transition (STWT) process. The STWT is thus conceptualized as a first attempt to access decent work under the influence of specific predictors, mediators, and moderators and leading to particular outcomes. Based on recent literature, we consider that (1) socioeconomic constraints and belonging to marginalized groups are contextual predictors of a successful transition; (2) psychosocial resources, including self-efficacy and adaptability, and vocational and work role identity, are mediators of the relation between contextual factors and a successful transition; (3) moderator factors include the education system, labor market conditions, social support, and critical consciousness; and (4) decent and meaningful work are the optimal outcomes of the STWT process.