Recent studies have demonstrated the efficacy of doxycycline as post-exposure prophylaxis (doxy-PEP) for sexually transmitted infection (STI) prevention, but little is known regarding patient beliefs and interest in doxy-PEP. We conducted a cross-sectional survey of adults (≥ 19 years) receiving care for HIV treatment (PWH) or prevention (pre-exposure prophylaxis, PrEP) between May-October 2023. The 32-question survey was organized into three parts: doxy-PEP awareness/beliefs/interest/concerns, sexual history, and demographics. Fishers Exact and Wilcoxon rank sum tests were used to compare responses between groups. Multivariate logistic regression identified predictive factors for doxy-PEP interest and concern(s). 166 participants completed the survey. Mean age was 43 years, 83% were male, 22% Black, and 13% Hispanic. Forty-one participants (25%) were on PrEP. Most respondents (75%) were unaware of doxy-PEP. Factors associated with doxy-PEP interest were respondents prescribed PrEP (aOR 2.67; 95% CI, 1.15-6.21) and belief of high risk for STI (aOR, 4.50; 95% CI, 2.24-9.07). Higher doxy-PEP concerns were associated with age ≤40 years (aOR, 3.10; 95% CI, 1.47-6.52), > high school education (aOR, 3.47; 95% CI, 1.64-7.33), and belief of high risk for STI (aOR, 2.58; 95% CI, 1.21-5.50). In this single-site cohort survey study, most respondents were unaware of doxy-PEP but expressed interest and low levels of overall concern. Clinicians should offer doxy-PEP access to all patients at high risk for STIs or requesting the treatment after shared decision-making discussions.