In this paper we examine the prevalence of problem behaviors in samples of adolescents who were adopted from a foreign country as infants or young children. We reviewed ten studies and performed a meta-analysis, comparing 2317 internationally adopted adolescents with 14,345 nonadopted adolescents. Results indicate that internationally adopted adolescents exhibit more behavior problems than do nonadopted adolescents (d = 0.08; p = 0.02), with the difference seen in externalizing (d = 0.11; p = 0.00), but not in internalizing (d = 0.05; p = 0.12), behavior problems. Significantly more total behavior problems were seen in adopted than in nonadopted girls (d = 0.10; p = 0.03), but not in adopted boys compared to nonadopted ones (d = 0.07; p = 0.22). All differences, however, were small. The differences between adopted and nonadopted adolescents were somewhat larger when we considered behavior problems in the clinical range. The majority of the adopted adolescents are well adjusted and do not display significantly more problem behaviors than do their nonadopted peers.