Maternal repartnering may have benefits for mothers and children. Yet, mothers with coresident children face more difficulty repartnering than other adults. Despite that shared physical custody and father involvement have increased over time, few studies have examined whether nonresidential father involvement and financial support are associated with subsequent maternal repartnering. Using data from the UK Millennium Cohort Study, we found a negative relationship between nonresident father involvement and subsequent maternal repartnering among mothers who were neither married nor cohabiting at childbirth. A potential explanation is that these parents may be engaged in fluid and uncertain relationships, and that the ambiguity thereof may discourage maternal repartnering. We found no association between father involvement and maternal repartnering for mothers who were cohabiting with or married to the father at the time of birth. Finally, we found no association between child support (maintenance) receipt and maternal repartnering, regardless of parental relationship status at the birth.