Summary.An investigation was carried out among 1,164 boys and 1,085 girls in single‐sex and mixed schools. Significant differences in favour of the girls were found in I.Q. attainment, and in attitude to school. It was also noted that attitudes to school grow more unfavourable from first to fourth form. Where there is a very substantial deterioriation in attitude there is a marked lack of improvement in attainment relative to I.