There is an established literature that suggests teacher perceptions of pupils affect how they interact with them, how they teach them and how they rate their ability and behaviour. Evidence also indicates that a teacher's perception of a child is often based on ascriptive characteristics such as gender, ethnicity and socio-economic background independent of a child's ability. This paper builds on the literature by examining whether teacher ratings of a child's ability and behaviour are associated with their perception of a particular ascriptive characteristic of the children they teach--their attractiveness. Using data from the National Child Development Study (NCDS) results show that not only do teachers rate the academic ability of students they perceive to be attractive more highly than less attractive students both in terms of their performance across different areas of learning (general knowledge, numbers, books and oral ability) and whether they show any outstanding potential, but they are also more likely to overrate and less likely to underrate their ability than other students. This is true even after controlling for a wide range of other factors related to the child, their family, their teacher and their school that could influence the relationship, many of which are shown to be independently related to teacher ratings.