Quantitative literature on international adoptees and racial/ethnic discrimination is lacking despite results in qualitative studies from Europe and the United States that have consistently indicated how racism constantly complicates adoptees’ everyday lives. To advance the literature, the present study examined the prevalence of perceived racial/ethnic discrimination among 213 adult international adoptees in Finland (59.6% women and 40.4% men, mean age 24.1 years), and the association between perceived racial/ethnic discrimination and psychological well-being indicators, including psychological distress and sleeping problems. In addition, we examined social support and sense of coherence as moderators of the association between perceived racial/ethnic discrimination and psychological well-being. Our results showed that, on average, adult international adoptees perceived racial/ethnic discrimination occasionally. Hierarchical linear regression analyses indicated a significant association between perceived racial/ethnic discrimination and psychological distress and sleeping problems. Additionally, a significant 2-way interaction of perceived racial/ethnic discrimination and social support indicated that the availability of social support may moderate the association between perceived racial/ethnic discrimination and psychological distress such that adoptees with high levels of social support may be protected from the harmful effects of discrimination. These results highlight the potential significance of social support in reducing the harmful effects of racial/ethnic discrimination on international adoptees.