The issue of teacher accountability has gained considerable attention in the last two decades. Developing out of the school accountability movements of the 1990s, teacher performance has become an increasingly contentious subject. While the importance of teachers is generally agreed, how to define effective teaching and then hold teachers accountable is fraught with complexity and differing approaches. This entry describes the three predominant models of teacher accountability: the traditional method where an administrator observes a classroom, the use of standardised observation measures, and the use of student test data to determine teacher effectiveness. The strengths and weaknesses of each approach are discussed and a real-world example is explained.