Authentic leaders are dedicated to achieving their goals with integrity, honesty, a strong sense of responsibility, and awareness, which builds trusting relationships with their employees. This trust boils down to numerous positive outcomes such as higher levels of thriving at work. Drawing on attachment theory, this study mainly investigates how authentic leadership can decrease attachment insecurity through which authentic leadership can impact their employees’ learning and vitality (i.e. two dimensions of thriving at work). This quantitative research has a deductive approach with a descriptive and correlational nature and employs a descriptive-survey methodology for data collection. Using A-priori sample size calculator for Structural Equation Models, the minimum statistical sample of the research was estimated to be 321 people. The data were collected from 330 employees of public service organizations in Kerman and Yazd through an online survey encompassing five scales with five-point Likert scales. The content and structure validities of the questionnaire were verified, and the reliability of all the scales was above the threshold of 0.7. The collected data were analyzed using SPSS, AMOS, and PROCESS Module. The results revealed that authentic leadership was negatively associated with both employees’ attachment anxiety and attachment avoidance. Meanwhile, these two attachment styles play mediating roles in determining how authentic leadership can affect employees’ learning and vitality. Notably, a leader’s authenticity, which features self-awareness, relational transparency, internalized moral perspective, and balanced processing, is more likely to reduce attachment insecurity and thus influence their thriving at work. This research extends our understanding of authentic leadership, attachment styles at work, and thriving at work. Practical implications and limitations are also discussed.