For many years there has been concern about whether sex bias exists in various assessments. A literature review reveals little if any sex bias in UK national assessments at GCSE. Oxford, Cambridge and RSA examiners, for three case study subjects, completed the Bem Sex Role Inventory, a self-report inventory that measures the extent to which respondents are sex-typed. The responses were used to investigate (1) whether there was any sex bias in the marking, (2) the relation between the sex of the examiners and their marking. In the English examination one question was biased by half a mark in favour of girls, and it was found that the more senior the examiner the more generous the marking. These findings concur with results in other areas like testing English as a second language. It is concluded that sex bias should be monitored but is unlikely to be found.