Background:There are few validated tools to measure stigma, particularly among children living with HIV and their families.Methods:This study was nested within a larger study that followed 240 child–caregiver dyads (children aged 10-15 years) at 8 clinics in western Kenya. The stigma instrument was administered to all child–caregiver dyads at 2 time points 6 months apart. The primary end point was to construct validity assessed by comparison to criterion constructs using generalized estimating equation models.Results:Mean age of child participants was 12.3 years and 52% were female. Generally, caregivers reported experiencing higher levels of HIV stigma compared to their children. Children (9%) and caregivers (14%) reported that HIV stigma made them feel stressed, anxious, and depressed. Child and caregiver stigma items showed high construct validity by emotional and behavioral outcomes.Conclusions:The stigma instrument showed high validity when compared to emotional and behavioral outcomes.