The present study uses the qualitative meta-synthesis to provide insight into elements that diminish teacher wellbeing and relevant school leadership practices that promote it in K-12 educational settings. Qualitative meta-synthesis is a type of systematic review that integrates the findings from qualitative studies with a common focus. Using several data sources: SCOPUS, Web of Science (WoS), Education Resources Information Center (ERIC), and Google Scholar, we have identified and synthesised findings from 29 qualitative articles. Drawing on the three steps of thematic synthesis, the results are presented in four main themes: (1) "Teacher autonomy and agency" that supports teachers' involvement in decision-making, their control on their work, and their innovative and creative works. (2) "Positive relationships and workplace environment" that ensure good and trusting relationships with the leader, social support, teamwork, inclusive practices, positive climate and work culture, accessible leadership, appreciation and professionalism. (3) "Professional and personal growth opportunities" that fit individual needs, do not add extra workload, enhance collaboration, and facilitate ideas implementation. (4) "Proactive support for wellbeing," such as prioritising teacher wellbeing and self-care, developing a systematic approach to wellbeing, and integrating wellbeing in school policies and decisions. Implications for policy, practice and future research are discussed.