In sub-Saharan Africa where sex work is often criminalized and highly stigmatized, female bar workers (FBWs) often serve as informal sex workers. However, little is known about the prevalence of HIV and HIV-related risk factors among FBWs in Dar es Salaam (DSM), Tanzania. Using an adapted Structural HIV Determinants Framework, we identified structural, interpersonal, psychosocial, and behavioral risk factors for HIV acquisition. We compared the prevalence of these risk factors and the prevalence of HIV among a random sample of 66 FBWs from DSM to an age-standardized, representative sample of female DSM-residents using data from the Tanzanian 2016 Demographic and Health and 2011-2012 AIDS Indicator Surveys. We found that, compared to other women in DSM, FBWs had elevated prevalence of all four groups of risk factors, often substantially so. Key risk factors included gender and economic inequalities (structural); sexual violence and challenges negotiating condom use (interpersonal); depression, post-traumatic stress disorder, and low social support (psychosocial); and history of unprotected sex, multiple sex partners, and frequent high alcohol consumption (behavioral). However, the HIV prevalence did not differ between FBWs (7.1%, 95% CI 3.7-13.3%) and survey respondents (7.7%, 95% CI: 5.3-11.1%), perhaps due to FBWs' higher-but still sub-optimal-engagement with HIV prevention strategies including condom use and HIV testing. FBWs' elevated exposure to structural, interpersonal, psychosocial, and behavioral risk factors for HIV acquisition but low HIV prevalence suggests that economic, psychosocial, and biomedical interventions to prevent HIV acquisition among FBWs in DSM are warranted.