System leadership is defined as the ability of an individual to lead across organizational boundaries to influence on a system level. Systems leadership describes the skills and strategies that can help individuals and organizations address complex challenges by working together to create systemic change. System leadership became an emerging practice encompassing a broad range of individual or organizational responsibilities that could be combined to create change within entire systems. Leaders who challenge the status quo to transform systems must be proficient system thinkers, because systems thinking provide the necessary mechanisms for achieving systemic change. The challenges facing humankind in the twenty-first century are systemic, requiring leaders who can influence change across organizational, geographic, and political/ideological boundaries. This entry consists of an introduction to system leadership and its history, and the barriers to implementing system leadership.