This study aims to review and quantify the value of several well-established positive leadership styles for employee work engagement in organizations. We perform both a quantitative and qualitative review (k = 86). Our (moderated) meta-analysis indicates that transformational, authentic, empowering, ethical, and servant leadership all share overlap in confidence and credibility intervals, resulting in a general association with work engagement of r = 0.47. Additional theoretical analysis revealed common ground of these positive leadership styles, i.e., exhibiting a moral perspective as a leader, role-modelling behaviour, follower self-determination, and positive social exchange with employees. Based on the studies in the sample, we also build an integrative research model with various mediators and moderators that have a well-established impact on work engagement. Moderators include follower characteristics and team- and organizational-level moderators. Mediators include psychological needs, trust, job resources, and organizational-level variables. The combination of a meta-analysis with systematic review and a research model may facilitate future research and supports practitioners to improve leadership. (download full article).