This paper reports on the longitudinal links between first-time mothers (N = 48) Adult Attachment Interviews (AAIs), provided during pregnancy, and their first-born children's AAIs, provided at age 16 years. The AAIs from the adolescents were scored for reflective functioning (RF), and this was found to be significantly linked to whether their mothers' AAI were appraised as free-autonomous/secure as opposed to insecure-dismissing. Discussion concerns the unique influence of mothers upon their first-born children's development of reflective functioning skills, including the understanding of mind and emotion. Fathers, for whom AAIs were also available, appeared to have no influence on this process. RF scores from the adolescents did not differ as a function of either the previously observed infant-mother attachment or the infant-father attachment.