Use of HIV testing services among FSW in sub-Saharan Africa (SSA) is below the desired UNAIDS target of 90%. We estimated the prevalence and factors associated with HIV testing among FSW in Dar es Salaam, Tanzania. A respondent-driven sampling method was used to recruit FSW aged 18. Modified Poisson regression models were used to determine factors associated with recent HIV testing. Of 958 surveyed FSW (median age 26 years), 85.4% (95% CI: 82.3, 88.1) reported to have ever been tested for HIV and 65.3% (95% CI: 61.2, 69.3) tested in the past 12 months. Condom use on the last day worked (prevalence ratio (PR) = 1.17; 95% CI: 0.99, 1.38), no or low self-perceived risk of HIV acquisition (PR = 1.16; 95% CI: 1.02, 1.32), having never felt stigmatized as a sex worker (PR = 1.18; 95% CI: 1.04, 1.33), and having been in contact with a peer educator (PR = 1.33; 95% CI: 1.18, 1.49) during the past year preceding the survey were associated with recent HIV testing. Interventions aiming to mitigate stigma due to sex work, improve health education to address risk perception as a barrier to HIV testing, and scaling up peer educator’s engagement should be given priority.