In Tanzania, disclosing HIV status to children is challenging despite WHO recommendations to inform children between the ages of 6 and 12 based on cognitive and emotional development. This study aimed to determine HIV status disclosure and related factors among children living with HIV in Tanzania. A study employing quantitative and qualitative methods was conducted from September 2021 to March 2022 among children aged 6-14 receiving HIV care. Semi-structured questionnaires were administered to disclosed and undisclosed children (through their parents/caregivers). The analysis included bivariate and multivariate logistic regression analyses and thematic content analysis for qualitative data. A total of 121 children participated in the quantitative analysis, with 51 (42%) aware of their HIV status. Multivariate analysis showed children aged 9-11 (OR=2.7
95% CI=0.8-9.0) and 12 years (OR=30
95% CI=7.2-124) were more likely to know their status than those aged 6-8. Having a treatment supporter/relative (OR=2.9
95% CI=1.0-8.2) was significantly associated with disclosure. Disclosure was not associated with depression. In-depth interviews revealed themes like disclosure challenges, stigma, and reasons for non-disclosure. HIV status disclosure in Kilimanjaro was associated with age and having a treatment supporter. Addressing age-related challenges and emphasizing the role of treatment supporters can improve disclosure outcomes.