The success of education reform depends on whether principals can effectively lead the school. Principal leadership is an important element of effective schools. It is time to rethink principal leadership assessment and put principals at the center of that discussion in an effort to build individual leadership capacity and school effectiveness. The Vanderbilt Assessment of Leadership in Education (VAL-ED) was developed by a team of researchers from Vanderbilt University. This model can be used by K-12 schools to assess principals’ leadership performance. The purposes of this article are to explore the development of the VAL-ED model and discuss its policy implications for principal leadership assessment in Taiwan. The VAL-ED model is an evidenced-based system that assesses principals’ leadership behaviors known to influence student learning. The conceptual framework of the VAL-ED model consists of six core components by six key processes. The core components are features of effective schools. The key processes are leadership behavior that principals can apply to lead their schools. It measures principals’ leadership behaviors for the purposes of diagnostic analyses, improvement feedback, progress monitoring, professional development, and performance evaluation. It is a useful model for assessing principals’ learning-centered leadership. This article proposes the following suggestions: (1) connecting principal leadership to student achievement; (2) balancing professional development and performance management; (3) constructing the professional standards for principals; (4) adopting 360-degree feedback assessment methods; and (5) developing the support system for principal leadership evaluation.