Background: Female entertainment workers (FEWs) in Cambodia who work at karaoke bars, massage parlors, and beer gardens experience a greater prevalence of human immunodeficiency virus (HIV) and sexually transmitted infections (STIs), psychological distress, substance use, and gender-based violence (GBV) than the general population. Reaching FEWs with health education and services has been difficult because of their hidden and stigmatized status. This study evaluates the Mobile Link intervention, aiming to improve FEWs’ health by connecting them to existing HIV, sexual and reproductive health, and GBV services using short message services and voice messages. Methods: This randomized controlled trial was conducted between March 2018 and June 2019. We employed a stratified random sampling method to select participants from five study sites. Initially, we randomly selected 600 participants from a list of 4000 FEWs by age group and study site and randomized them to intervention or standard care control arms. The primary outcome measures included self-reported HIV and STI testing, condom use, and contraceptive use. Secondary outcomes included contact with outreach workers, escorted referral services use, forced drinking, and GBV experiences. Intervention effects were modeled using repeated measures, multilevel mixed-effects logistic regression. Findings: We included 218 FEWs intervention and 170 FEWs in control arms in the per-protocol analyses after removing dropouts. No significant differences between intervention and control groups over time were observed for any primary outcomes in the fully adjusted models. However, evidence of positive intervention effects was detected for the following secondary outcomes: contacting an outreach worker (group by time 2 AOR: 3·288, 95% CI: 1·277-8·469), receiving an escorted referral (group by time 2 AOR: 2·861, 95% CI: 1·089-7·518; group by time 3 AOR: 8·150, 95% CI: 1·650-40·250), and never being forced to drink at work (group by time 3 AOR: 3·945, 95% CI: 1·622-9·597). Interpretation: The Mobile Link intervention effectively connected FEWs with outreach workers and escorted referrals. Reductions in forced drinking at work were also significantly larger in the intervention group than the control group. Longer-term messaging may increase access to services and may impact FEWs’ health outcomes in the future. Trial Registration: The Mobile Link trial has been registered with ClinicalTrails.gov (No. NCT03117842). Funding Statement: This study was funded by the 5% Initiative and Expertise France (Grant No. 16SANIN210). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: This research received approval from the Institutional Review Board of Touro University (No. PH-0117) and the National Ethics Committee for Health Research of the Ministry of Health in Cambodia (No. 142HECHR).