Introduction: Sustained undetectable viral loads (UDVLs) on antiretroviral therapy (ART) eliminate sexual HIV transmission. We measured prevalence and correlates of sexual anxiety among women living with HIV. Methods: We used questionnaire data collected between August 2013 and May 2015 from 1422 women ≥ 16 years in the Canadian HIV Women’s Sexual and Reproductive Health Cohort Study. Among women reporting consensual sex in the past month (n = 474), we determined the proportion who reported high anxiety (“always/usually became anxious or inhibited during sexual activity with a partner”), low anxiety (“sometimes/seldom”), and no anxiety. Logistic regression identified medical, psychological, relational, and social correlates, including awareness of ART prevention benefits (i.e., “makes the risk of transmitting HIV a lot lower”). Results: Cohort diversity is reflected in age (range 17–66; median 39), gender (5.7% trans), ethnicity (41.6% White, 24.5% Indigenous, 27.0% African/Caribbean/Black), sexual orientation (14.2% lesbian/queer), and time living with HIV (range 18 days–30 years.). Overall, 58.6% reported feeling no sexual anxiety, while the remainder said that they always/usually (14.6%) or sometimes/seldom (26.8%) became anxious or inhibited during sex. Current sex work, previous illicit drug use, and depression were associated with higher adjusted odds of sexual anxiety, while greater emotional closeness and more equitable relationship power were associated with lower odds. There was no correlation between awareness of ART prevention benefits and sexual anxiety. Conclusions: Relatively few women reported high anxiety during sex with a partner. This was more socially and relationally influenced than linked to understanding ART prevention benefits. Policy Implications: Women living with HIV should be supported to have great sex, free from worry, by tackling unequal power in women’s intimate relationships, lack of access to resources, and mental health difficulties.