Successive governments in England have regarded classroom observation as an essential tool for monitoring and improving teacher performance. Despite its importance in national policy for teacher development, the impact of classroom observation on individual teachers, and on improving quality and standards in teaching and learning, remain under-researched areas. Further education (FE) in general, and FE teachers in particular, have received sparse attention. This paper adopts a theoretical framework grounded in aspects of assessment theory to explore some of the consequences of using observation to assess, monitor and raise standards of classroom performance in the FE workforce. It draws on findings from a mixed-methods study, involving questionnaires and semi-structured interviews, conducted in 10 FE colleges situated across the West Midlands region of England. The paper concludes by situating the findings against the broader backdrop of research into teachers' continuing professional development and, in so doing, raises questions about the fitness for purpose of prevailing observation assessment regimes in FE and the extent to which these systems are able to achieve their purported goals.