We examine the effects of transitions in marital and parenthood status on 1,091 men's and women's housework hours using two waves of data from an Australian panel survey titled Negotiating the Life Course. We examine transitions between cohabitation and marriage, and from cohabitation or marriage to separation, as well as transitions to first and higher-order births. We find extraordinary stability in men's housework time across most transitions but considerable change for women in relation to transitions in parenthood. Our results suggest that the transition to parenthood is a critical moment in the development of an unequal gap in time spent on routine household labor.