Waning donor funding and poor country ownership of HIV care programmes are challenges for the sustainability of care for people living with HIV (PLHIV) in Nigeria. Health insurance presents a viable alternative for funding of HIV care services. This study assessed the determinants of willingness to participate in health insurance amongst PLHIV in a tertiary hospital in South-East Nigeria. Across-sectional survey was conducted amongst 371 PLHIV on treatment at Federal Teaching Hospital, Abakaliki, Nigeria, using a semi-structured, interviewer-administered questionnaire. Chi-square test and logistic regression were conducted with SPSS version 20 at 5% level of significance. Respondents were mostly males (51.8%) with a mean age and monthly income of 45.4 ± 10.3 years and $74.1 ± 42, respectively. Majority were willing to participate (82.5%) and to finance health insurance (65.2%). The major reasons cited by those unwilling to participate were poor understanding of how the system works and lack of regular source of income. The predictors of willingness to participate were female gender (adjusted odds ratio [AOR] = 2.9; 95% confidence interval [CI]: 1.6-5.7), being currently unmarried (AOR = 4.3; 95% CI: 2.3-7.8), being self-employed (AOR = 2.2; 95% CI: 1.2-3.9), having family size >5 (AOR = 3.1; 95% CI: 1.7-5.9) and having less than secondary school education (AOR = 4.3; 95% CI: 2.3-7.8). Majority of the respondents surveyed were willing to participate in, and finance health insurance. Willingness to participate was more amongst vulnerable subgroups (females, unmarried, self-employed, poorly educated and those with large family size). We recommend the inclusion of health insurance in the care package of PLHIV.