Summary. An examination of previous work on the relation of season of birth to educational backwardness suggests that an undue preponderance of Summer‐born children might be found in special schools for the educationally subnormal. This suggestion is verified for a population of 265 children drawn from such schools. Two possible reasons for this effect are considered, that of differential entry to infant school, and the ‘age‐group‐position’ effect. It was not found possible to distinguish these effects in this study. The results of this study are collated with those of previous investigations into the relationship of season of birth and various forms of handicap to show the relative consistency of different evidence. Increased flexibility of educational organisation and the extension of services for the educational guidance of individual children are advocated.