The associations between maternal labour force participation and child academic achievement were examined in a birth cohort of New Zealand children who have been studied from birth to age 18. The results of this analysis suggested the presence of small associations between the extent of maternal labour force participation and scores on standardised tests of word recognition, reading comprehension, and mathematical reasoning. Similar associations were found between maternal labour force participation and success in school leaving examinations. These associations arose predominantly because children whose mothers worked had better performance than children whose mothers who had not worked in paid employment. However, patterns of maternal labour force participation were also related to a series of family and child factors including: maternal education, family socioeconomic status, race, birth order, family composition, early mother–child interaction, and child IQ. Adjustment for these factors reduced associations between maternal labour force participation and academic achievement to the point of practical and statistical nonsignificance. These results were found to be robust and similar conclusions were found for (1) a range of measures of maternal labour force participation, and (2) subgroups of the cohort defined by gender, socioeconomic status, ethnicity, or family type.