This study evaluated the associations between filial relationships and young adults’ adjustment to the period of emerging adulthood in adoptive families. Adopted individuals’ attachment to their adoptive parents and affect about adoption were assessed at adolescence and young adulthood and compared with their feelings of negative instability about the period of emerging adulthood. Findings demonstrate that affect about adoption and attachment to each parent during adolescence and emerging adulthood are associated with negative instability in emerging adulthood. Specifically, individuals whose attachment to each parent and affect about their adoption remained high from adolescence to emerging adulthood had the lowest ratings of negative instability in emerging adulthood whereas individuals whose attachment and affect remained low across this period had the highest ratings of negative instability. Additionally, results found more mobility than stability in attachment and adoption affect across this time.