Newly available survey data allow the investigation of the educational and employment opportunities open to Roman Catholics in Scotland in the mid-20th century. Previous research has shown that Catholic disadvantage in education and the labour market in the early 20th century had weakened or vanished by the end of the century, and that the main change in that respect had come with the advent of comprehensive secondary schooling in the 1960s. However, the extension of Catholic secondary schooling started in the 1920s. The data used here allow an investigation of whether the Catholic disadvantage was mitigated by these earlier reforms, and thus allow an assessment of whether a selective school system was able to overcome an important dimension of social disadvantage. The data come from a cohort study of a representative sample of people born in 1936 (first surveyed in 1947 and followed up annually to 1963). Evidence is available on social background, on cognitive ability measured at age 11, on secondary school courses, on educational achievement after leaving school, and on social-class status at age 27. The conclusions are that the continued social disadvantage of Catholics was not due to any aspect of the school education which they had received.