This study investigated attachment-related behavioural problems and their change over time among internationally adopted toddlers (N=171, boys 40%) in Finland. The parents filled in questionnaires posted in 2007 and again in 2009. At the baseline (on average, 1.9years from adoption), the mean age of the adoptees was 2.8years. The comparison group (N=244, boys 46%) was collected through well-baby clinics. Results from the paired t-test and mixed models showed that the adoptees' attachment-related behavioural problems decreased during the 2-year follow-up and that they did not manifest more problems than their age-mates any more 4years after adoption. The decrease in behavioural problems was associated with the child's female gender, country of origin and adoptive parents' positive experience about adoption. A child's stereotypic or self-injurious behaviour was not associated with the change in attachment-related behaviour over time, although both were associated with behavioural problems. Copyright (c) 2014 John Wiley & Sons, Ltd.