This paper examines the relationship between birth order and later educational outcomes in a birth cohort of more than 1,000 New Zealand young adults studied to the age of twenty-five. Being later born was associated with gaining fewer educational qualifications at secondary level and beyond. The use of nested models to control for the confounding effects of family size on birth order revealed that birth order effects on educational attainment were not disguised by family size effects. Following adjustment for potentially confounding factors, there remained a statistically significant association between being later born and a lower likelihood of obtaining educational qualifications. It was concluded that the intra-family dynamics initiated by birth order may have a lasting effect on the individual in terms of later educational and achievement outcomes. (Contains 5 tables.)