Teacher leadership is a critical aspect of school change while there is lack of a consistent definition for it. This examines teacher leadership conceptualization and its associated outcomes. The review of 33 articles published 2018-2023 focused on teacher leadership in K-12 setting, found that many authors relied on established definitions, with few offering their own interpretations. These articles depict teacher leadership as an informal and individual form of leadership. The analysis revealed outcomes of teacher leadership at school development level; teacher-level benefits including professional growth; and student-level impacts such as increased achievement and motivation.