This two wave panel study examined child self-regulation as a potential mediator of the relationship between marital attachment security in parents and anxiety in their adolescent child. Data for this study were taken from the two parent families in waves three and four of the Flourishing Families project which included 335 two-parent families with children between the ages of 14 and 16. Both parents and child completed the Novak and Clayton (2001) Self-regulation Scale with the child's self-regulation as the target, and both husbands and wives completed a modified version of the Experiences in Close Relationships Questionnaire (Fraley, Waller, & Brennan, 2000) for their attachment security in their marriage. Children completed the generalized anxiety subscale of the Spence Anxiety Inventory (Spence, 1998) at both waves. Findings showed that child self-regulation was a process through which wife insecure attachment in her marriage indirectly influenced child anxiety in both boys and girls. Self-regulation also mediated the relationship between husband insecure couple attachment and child anxiety for boys but not for girls. Only the mother insecure marital attachment was directly related to both boys' and girls' anxiety. Implications of the findings for family therapy are discussed.