This paper reports data from 306 Irish-speaking partakers aged 6–13 years from a range of language backgrounds, most of whom live in Gaeltacht (officially designated Irish-speaking) areas. Information was gathered from parents on children’s home language and new measures of receptive and productive use of grammatical gender marking in Irish were administered. Performance on these measures is compared with scores on standardised measures of Irish and English reading vocabulary, as well as teacher and parent ratings.