The adoption of late-placed children could be considered a powerful factor of change in their lives (Juffer et al., 2011; Palacios & Brodzinsky, 2010; Van den Dries, Juffer, Van IJzendoorn, & Bakermans-Kranenburg, 2009) enabling them to revise their insecure and/or disorganized Internal Working Models (IWMs), and this change seems to be strongly associated with secure IWM of adoptive parents (Steele et al., 2008), specifically with maternal ones. Our goals were: 1) to explore the change of IWMs in late-adopted children in a long-term follow-up, from the placement to adolescence, and 2) to capture the impact of their maternal attachment models. Longitudinal research with attachment assessment of late-adopted children and their mothers was performed at three steps: time 1 (T1) at the beginning of adoption, time 2 (T2) 6/7 months later and time 3 (T3) around 6/7 years after T2. We found an over-representation of insecure classifications at T1, a significant revision of them towards security at T2, which appears to be confirmed at T3. Furthermore, the children showing the change at T2 have predominantly adoptive mothers with secure-autonomous IWMs. A significant correlation emerged between children's and mothers' secure-insecure classification at T3. These findings seem to suggest that late-placed children would be able to gradually revise their attachment patterns and the attachment security of their adoptive mothers would make it more likely to occur.