Objective: The purpose of this study is to explore principals' perspectives on the concept of teacher leadership, the strategies that they employed to support teacher leadership practice and the challenges and issues that principals faced while implementing teacher leadership. Methodology: This qualitative case study uses interview sessions with 10 purposely selected principals from various types of secondary schools. All schools are public schools that are administered and funded by the Ministry of Education, Malaysia. Findings: The study reveals that principals had a comprehensive understanding of the concept of teacher leadership; in fact, principals were able to list teacher leaders' characteristics and provide definitions for the concept of teacher leadership. In exploring principals' strategies to support teacher leadership practice, five themes emerged: developing future leaders, a mentoring programme, involving more teachers as teacher leaders, practising an 'open door' policy and providing more opportunities for teachers to offer mutual assistance. In terms of the challenges for teacher leadership practices, principals shared particular issues such as the unwillingness of teachers to become teacher leaders due to their heavy workloads and challenges in eading senior teachers. Significance: This study supplements the literature that explores teacher leadership within the Malaysian schooling context, which has hitherto been understudied. Thus, the concept of teacher leadership needs more in-depth investigation and evaluation to ascertain its suitability within Malaysia's educational system. For the Ministry of Education, this study notes some practical implications for improving teacher leadership in Malaysian schools.