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 who were coresident over Years 1-3 and 1,376 couples who were coresident over Years 3-5 (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. In general, married and cohabiting couples were similar in how relationship quality and parenting were linked.