Background. With prolonged survival and aging of persons with HIV on combination antiretroviral therapy (ART), hypertension has emerged as a significant cause of morbidity and mortality globally. However, little is known about the burden of this comorbid condition among adults living with HIV in sub-Saharan Africa. In this study, we aimed to determine the prevalence and factors associated with hypertension among HIV-infected patients receiving ART in Northeast Ethiopia. Methods. A cross-sectional study was conducted at the ART clinic of Dessie Referral Hospital, Northeast Ethiopia, between January and May 2018. HIV-infected patients who were on ART for at least 12 months were included in the study. Demographic, clinical, and laboratory data were collected from each participant. Hypertension was defined as a systolic blood pressure (BP) of ≥140 mmHg and/or diastolic BP of ≥90 mmHg or a reported use of antihypertensive medication. Univariable and multivariate analyses were performed to identify factors associated with hypertension. Results. A total of 408 patients were studied with a mean (±SD) age of 37 ± 10.3 years, and 66.9% were female. The prevalence of hypertension was 29.7% (95% CI, 25.3–35.0%). Nearly 75% of the patients with hypertension were previously undiagnosed. In a univariate analysis, older age, male gender, a family history of hypertension, duration of HIV infection, duration on ART, high body mass index, low CD4 count, diabetes, and renal impairment were associated with hypertension. Multivariate analysis revealed older age (AOR = 2.08; 95% CI, 1.13–3.83), male gender (AOR = 1.64; 95% CI, 1.01–2.65), longer duration on ART (AOR = 1.91; 95% CI, 1.14–3.20), high body mass index (AOR = 3.32; 95% CI, 1.13–9.77), and diabetes (AOR = 2.76; 95% CI, 1.29–5.89) as independent risk factors of hypertension. Conclusions. Hypertension is highly prevalent among HIV-infected patients on ART attending our clinic in Northeast Ethiopia but is mostly undiagnosed. These findings highlight the need for integrating hypertension management into routine HIV care to prevent adverse outcomes and improve health of people living with HIV on ART.