We used data from the Fragile Families and Child Wellbeing Study to examine how couple relationship quality and parental engagement are linked over children's early years-when they are infants, toddlers, and preschoolers. Our sample included 1,630 couples that were coresident over years 1 to 3 and 1,376 couples that were coresident over years 3 to 5 (1,196 over both periods). Overall, we found that better relationship quality predicted greater parental engagement for both mothers and fathers-especially in the infant to toddler years; in contrast, we found little evidence that parental engagement predicted future relationship quality. Married and cohabiting couples were generally similar in how relationship quality and parenting were linked.