Purpose: The main aim of the current study was to examine how primary psychopathy may interact with period of confinement to predict Criminal Social Identity (CSI) scores, while controlling for covariates. Methods: The Measure of Criminal Social Identity, Levenson Self-report Psychopathy Scale, and the Measure of Criminal Attitudes and Associates were administered to 126 male juvenile offenders incarcerated in prisons in Khyber Pakhtunkhwa. Results: Results indicated no significant direct relationship between period of confinement and CSI scores. However, as expected, a significant moderating effect of primary psychopathy on the association between period of confinement and CSI scores was observed while controlling for covariates. Specifically, the significant effect of period of confinement on CSI was observed only for those participants who scored higher (1 SD above the mean) on primary psychopathy (affective and interpersonal features). Conclusion: For incarcerated juveniles with greater primary psychopathic traits, the formation and/or intensification of CSI may be an adaptive response to incarceration.