To investigate the antecedents of employee authenticity systematically from the organizational context and to examine the mediating role of basic psychological need satisfaction in this relationship, we conducted a three-wave study among 1349 Chinese employees. The results show that the four categories of the organizational context investigated, i.e., organization, leaders, colleagues and task, significantly and uniquely predicted employee authenticity. Specifically, in the organization category, both organizational support and organizational justice positively predicted employee authenticity. In the leader category, inclusive leadership positively predicted employee authenticity. In the colleague category, high-quality relationships with colleagues was a significant and positive predictor. In the task category, job demands negatively predicted employee authenticity, while job autonomy and possibilities for development positively predicted employee authenticity. In addition, drawing on self-determination theory (SDT), basic psychological need satisfaction was found to mediate the relationships between all these organizational contextual factors (including authentic leadership) and employee authenticity. Our study investigated the antecedents of employee authenticity systematically and comprehensively from the perspective of organizational context and revealed the mechanism underlying these relationships, thereby extending our understanding of how employee authenticity forms in organizations and shed light on managerial practices to promote employee authenticity.