Globally, there are numerous debates on what constitutes an effective school. This book therefore determines and defines the factors contributing to the effectiveness and improvement of secondary schools in the Free State Province of South Africa. The book presents a comprehensive literature review which encompasses the policy context of school effectiveness internationally and in South Africa, definitions of the concept of school effectiveness, models of school effectiveness, methods of evaluating school effectiveness, the relationship between school effectiveness and school improvement, change and school improvement, approaches to school improvement and the characteristics of effective schools. The Index of School Effectiveness and Improvement (ISE&I) is suggested and discussed, which is a document that schools can use to review and enhance their effectiveness. ISE&I is a model developed in the course of this study to assist schools in improving their effectiveness. This book is intended for educational managers, administrators and governors of educational institutions in South Africa and in countries with similar educational contexts.