INTRODUCTION: Our study describes changes in HIV care service delivery and continuity of HIV antiretroviral therapy (ART) for people living with HIV (PLHIV) during the 8 weeks before and after diagnosis of the first coronavirus disease 2019 (COVID-19) cases in Haiti on March 19, 2020. METHODS: Using data from 96 out of 167 health facilities offering ART services, we compared four ART program indicators: (1) count of HIV visits; (2) proportion of ART dispenses in community-based settings (DAC); (3) proportion of multi-month dispensing of ART medications > 6 months (> 6 m MMD); and (4) proportion of timely ART refills. We used uncontrolled interrupted time series (ITS) models to estimate slope and level changes in each indicator with the arrival of COVID-19. RESULTS AND DISCUSSION: From week 1 to week 16, the average number of HIV visits fell from 121.5 to 92.5 visits, the proportion of DAC rose from 22.7% to 36.7%, the proportion of > 6 m MMD rose from 29.4% to 48.4%, and the proportion of timely ART refills fell from 51.9% to 43.8%. The ITS models estimated abrupt increases of 36% in > 6 m MMD (p < 0.001) and 37% in DAC (p < 0.001) at the time of COVID-19 arrival, and no change after arrival of COVID-19. The was an abrupt decline of 18% in timely ART refills with the arrival of COVID-19 and a decline of 1% per week thereafter, both non-statistically significant changes. CONCLUSIONS: The sudden changes in HIV service utilization represent dramatic adaptations needed to mitigate primary and secondary effects of the COVID-19 pandemic on PLHIV. This study underscores the urgency of optimizing ART delivery models in Haiti and beyond, in order to maintain progress toward HIV epidemic control.