We investigated the extent to which relationship status and age at birth explain the education gradient in whether a woman’s pregnancy leading to her most recent birth was intended or not. Our data came from wave 5 (2005) of the Household Income and Labour Dynamics in Australia survey (HILDA) (n = 1,751). We found an education gradient in intended births, where less educated women were more likely to report an unintended most recent birth. Part of this was explained by the fact that less educated women were younger when they give birth and less likely to be married—characteristics predictive of unplanned births. To better understand education differences in having unintended births further research needs to focus on the role played by education differences in abortion and contraceptive behaviour.