Teachers who lack professional maturity will never be able to be responsible teacher leaders; hence, school leaders who strive for school improvement constantly try to introduce various alternative practices, and teacher leadership may be among these. Teacher leadership is defined in numerous ways: Some understand it as teachers who have taken on leadership roles and additional professional responsibilities. The major argument in this paper is that teachers need to be professionally matured if they are to be able to be effective teacher leaders. Effective schools are likely to be those where leadership permeates throughout the entire organisation. This qualitative study was conducted in two Gauteng and two Eastern Cape historically black schools, and data were collected through interviews and observations. The results demonstrate that there are several reasons as to why some teachers may fail or be reluctant to be teacher leaders. Furthermore, the study reveals that teacher leadership needs visionary school leaders who will employ the critical practices of teacher leadership to attain school improvement.