ABSTRACT Adherence to antiretroviral therapy (ART) is critical for people with HIV (PWH) to achieve and maintain virologic suppression and minimize drug resistance. This study aimed to use real-world data to characterize ART adherence and its effect on quality of life (QoL) in PWH. Data were drawn from the Adelphi HIV Disease Specific Programme™, a cross-sectional survey of physicians and PWH in the United States, conducted June–October 2021. Demographic and clinical characteristics, ART adherence and treatment satisfaction for PWH were reported by physicians. PWH completed standardized QoL questionnaires. Adherence level was categorized into completely, mostly and less adherent. Regression analysis was used to investigate factors associated with adherence and the association between adherence and QoL measures. Of 578 PWH, 189 (32.7%) were not completely adherent. Having AIDS-defining illnesses, anxiety/depression or being symptomatic was significantly associated with lower adherence. Reasons for poor adherence included forgetting, difficulties integrating into routine and side effects. QoL scores were significantly higher in the completely adherent group. These findings highlight the strong association between suboptimal adherence and QoL among PWH and key factors and PWH reasons that may lead to suboptimal adherence. Interventions aimed at improving the QoL of PWH by understanding these factors are warranted.