HIV pre-exposure prophyalxis (PrEP) might lead individuals to view serodisclosure as unnecessary. We examined the prevalence of non-disclosure and lack of knowledge of partner status in a global cohort of men who have sex with men (MSM) and transgender women (TW) enrolled in the iPrEx Open Label Extension (OLE). We calculated prevalence ratios by fitting a logistic model and estimating predicted probabilities using marginal standardization. Prevalence of non-disclosure and lack of knowledge of partner status were highest in Thailand (73% and 74%, respectively) and lowest in the USA (23% and 37%, respectively). In adjusted analyses, PrEP use was not significantly associated with non-disclosure or lack of knowledge of partner status (p-values>0.05). We found that relationship characteristics were significantly associated with both outcomes. Non-disclosure was higher among casual (adjusted prevalence ratio [aPR] 1.54, [95% confidence interval 1.24–1.84]) and transactional sex partners (aPR 2.03, [1.44–2.62]), and among partners whom participants have known only minutes or hours before their first sexual encounter (aPR 1.62, [1.33–1.92]). Similarly, participants were less likely to know the HIV status of casual partners (aPR 1.50, [1.30–1.71]), transactional sex partners (aPR 1.62, [1.30–1.95]), and those they have known for only days or weeks (aPR 1.13, [0.99–1.27]) or minutes or hours (aPR 1.27, [1.11–1.42]). Our findings underscore the role of dyadic factors in influencing serodisclosure. Comprehensive risk reduction counseling provided in conjunction with PrEP that address relationship characteristics are needed to help patients navigate discussions around HIV status.