The main aim of the present study was to examine the psychometric properties of the Inventory of Callous-Unemotional Traits (ICU) among a sample of incarcerated male Portuguese juvenile offenders (N = 221). Based on this sample, the Portuguese version of the ICU demonstrated promising psychometric properties, namely, in terms of factor structure, internal consistency, convergent validity, discriminant validity, and concurrent validity that generally justifies its use among this population. Statistically significant associations were found with conduct disorder, age of criminal onset, crime seriousness, physical violence use in committing crimes, alcohol use, cannabis use, and cocaine/heroin use.