BACKGROUND: The coronavirus disease (COVID-19) pandemic causes fear and anxiety symptoms on some vulnerable populations such as patients living with human immunodeficiency virus (HIV) (PLWH). Physical distancing (during consultation in the clinic) and isolation restrictions will likely have a negative impact on/disruption to all care continuum services of HIV diseases although healthcare services and access to anti-retroviral therapy (ART) have continued to operate. OBJECTIVE: To investigate the factors associated with ART adherence among PLWH during the COVID-19 pandemic. METHODOLOGY: A cross-sectional study was conducted on 324 PLWH who had been on ART for at least 6 months between June 2020 and January 2021. A semi-structured questionnaire was used to interview participants to collect data on sociodemographic characteristics and other factors. RESULTS: Of 324 PLWH taking ART, 264 (81.48%) had high adherence (≥95%) and 60 (18.52%) had low adherence (< 95%). Factors independently associated with high ART adherence were employment status (adjusted odds ratio (AOR): 0.030, 95% confidence interval (CI): 0.010-0.088; < 0.001), type of antiretroviral (ARV) (AOR: 3.101, 95% CI: 1.137-8.456; = 0.027), family support (AOR: 0.157, 95% CI: 0.052-0.475; = 0.001), the perception that the COVID-19 pandemic negatively impacts the ability to attend clinics (AOR: 7.339, 95% CI: 1.46-36.79; = 0.015), and the perception that the COVID-19 pandemic negatively impacts the ability to take ART (AOR: 10.611, 95% CI: 2.98-37.72; < 0.001). CONCLUSIONS: During the COVID-19 pandemic, factors associated with high ART adherence among PLWH attending the Hospital of Wangaya in Denpasar, Bali, Indonesia were employment status, ART type [non-fixed dose combination (FDC)], family support, and the perception that the COVID-19 pandemic negatively impacts the ability to attend clinics and to take ART.