Disclosure of HIV-positive status has important implications for patient outcomes and preventing HIV transmission, but has been understudied in TB-HIV patients. We assessed disclosure patterns and correlates of non-disclosure among adult TB-HIV patients initiating ART enrolled in the START Study, a mixed-methods cluster-randomized trial conducted in Lesotho, which evaluated a combination intervention package (CIP) versus standard of care. Interviewer-administered questionnaire data were analyzed to describe patterns of disclosure. Patient-related factors were assessed for association with non-disclosure to anyone other than a health-care provider and primary partners using generalized linear mixed models. Among 371 participants, 95% had disclosed their HIV diagnosis to someone other than a health-care provider, most commonly a spouse/primary partner (76%). Age, TB knowledge, not planning to disclose TB status, greater perceived TB stigma, and CIP were associated with non-disclosure in unadjusted models (p < .1). In adjusted models, all point estimates were similar and greater TB knowledge (adjusted odds ratio [aOR] 0.59, 95% confidence interval [CI] 0.39–0.90) and CIP (aOR 0.20, 95% CI 0.05–0.79) remained statistically significant. Among 220 participants with a primary partner, 76% had disclosed to that partner. Significant correlates of partner non-disclosure (p < .1) in unadjusted analyses included being female, married/cohabitating, electricity at home, not knowing if partner was HIV-positive, and TB knowledge. Adjusted point estimates were largely similar, and being married/cohabitating (aOR 0.03, 95% CI 0.01–0.12), having electricity at home (aOR 0.38, 95% CI 0.17–0.85) and greater TB knowledge (aOR 0.76, 95% CI 0.59–0.98) remained significant. In conclusion, although nearly all participants reported disclosing their HIV status to someone other than a health-care provider at ART initiation, nearly a quarter of participants with a primary partner had not disclosed to their partner. Additional efforts to support HIV disclosure (e.g., counseling) may be needed for TB-HIV patients, particularly for women and those unaware of their partners’ status.