People with HIV (PWH) are disproportionally affected by mpox and at risk of severe complications. We assessed mpox knowledge, adoption of preventive behaviors, and vaccination attitudes among PWH enrolled in a longitudinal HIV cohort in Washington, DC, the DC Cohort. We conducted uni- and multivariable analyses comparing participants by vaccination status and HIV risk group, and multinomial regression to identify factors associated with vaccine acceptance. Among 430 PWH, 378 (87.9%) were aware of mpox. Among 373 participants with vaccination status data, 101 (27.1%) were vaccinated, 129 (34.6%) planned to vaccinate, and 143 (38.3%) did not plan to vaccinate. The three vaccination groups differed significantly by age, race, education, HIV risk group, recent STI status, and level of mpox worry (all p < 0.05). A higher proportion of men who have sex with men (MSM) reported limiting their number of sexual partners compared to non-MSM (p < 0.0001). Multinomial regression models comparing vaccinated to unvaccinated PWH found age, education, mode of HIV transmission/gender, and survey period were significantly associated with vaccination status (all p < 0.05). High levels of mpox awareness were observed among this cohort of PWH with more MSM employing risk reduction behaviors and being vaccinated. Ensuring that PWH, regardless of gender, sexual orientation, or age, understand the risks of mpox may improve vaccination uptake.