Background: Research evidence about adopted children’s social functioning is scarce and inconsistent. This might be due to differences in the adoptees’ characteristics/background, as well as to the use of different social constructs, instruments and informants, across adoption studies.

Aim: The main purpose of this study is to explore the behavioral dimensions of adoptees’ social competence (social skills and its competing problem behaviors), using multiple informants.

Method: The Social Skills Improvement System-Rating Scale was used to evaluate a set of social skills and problem behaviors in 83 adopted Portuguese children, aged 8 to 10, by themselves, their adoptive mothers and fathers and their main teachers (total of 332 evaluations).

Results: Descriptive statistics revealed normative figures for the subscales, except for children’s hyperactivity and externalization problems, which were above average according to adult informants. Data did not provide a clear pattern of relationships between the child’s pre- and post-adoption characteristics and informants’ ratings. The experience of neglect lived within the birth family was related to children’s lower empathy reported by teachers and higher internalizing problems rated by mothers; the children’s self-reports of empathy were positively correlated to the time spent within their birth family. The time spent in care was positively related to mothers’ ratings of hyperactivity, and the higher the number of children’s pre-adoption transitions, the lower their empathy and engagement reported by teachers. The time spent within the adoptive family was positively correlated to children’s empathy rated by fathers, and negatively to externalizing and bullying problems reported by mothers and teachers. Cross-informants’ similarities and differences were observed. Both in social skills and problem behaviors (except for internalizing), children provided the most favorable ratings. Children’s internalizing scores were higher in self-reports, and lower in parents’ reports. Some informant’ effects were also observed, particularly strong in problem behaviors’ evaluations, proving the bias of using a single informant perspective.

Conclusions/Implications: Using a multi-informant approach provides a panoramic perspective richer and more complete than the tunnel vision afforded by any single informant. Informants are not interchangeable and each one has a specific perspective developed in a specific context. Finally, perhaps because adoptees-related variables are only part of a more complex developmental picture, relationships between adoptees’ pre- and post-adoption characteristics and their social functioning seems to be weak and of little consistency. This is the first study on adoption-research using four informants to evaluate the behavioral dimensions underlying the school-aged adoptees’ social competence, bringing new evidence for the inconsistent findings described in this field of research.