In terms of absolute or 'raw' examination and test scores, those maintained schools in England designated as Roman Catholic by the Department of Education and Skills appear, on average, to achieve higher scores than the mean of non-Catholic schools. Similar findings have been reported about Catholic schools in other differing educational systems, most extensively in the US. A range of possible causes has been advanced to explain the findings though there is little empirical research to determine causality with any certainty. The main source of evidence derives from studies in the US. While they can offer some useful insights they relate to a different educational culture. This paper attempts to contribute to and evaluate the current debate about possible reasons for the high levels attainment of pupils attending Catholic schools in England. However, in the light of the limited available evidence it is, inevitably, somewhat speculative.