Two studies tested whether children’s attitudinal ambivalence toward their parents is related to their attachment styles within relationships. Across both studies, children who were ambivalent toward their father were less securely attached in their relationships than were children who were nonambivalent toward their father. Study 1 also showed that the relation between attitudinal ambivalence and secure attachment in relationships was independent of attitude valence, attitudinal embeddedness, attitudinal inconsistency, and attitudinal commitment. Study 2 demonstrated that the relation between attitudinal ambivalence and general attachment style was mediated by children’s secure attachment to their father. There were similar relations between participants’ ambivalence toward their mother and their attachment styles in relationships, but these relations were weaker and less consistent across studies. An explanation for the unique effect of ambivalence toward fathers is discussed.