Mobile Link is a mobile phone-based intervention to increase access to, and use of, health care services among female entertainment workers in Cambodia who face higher risks for specific diseases and gender-based violence. A multisite randomized controlled trial showed that Mobile Link connected female entertainment workers with outreach workers for information and escorted referrals after 6 months but did not lead to statistically significant improvements in HIV and sexually transmitted infection testing, contraceptive use, and condom use. This study aims to conduct a 3-part economic evaluation of Mobile Link to understand its costs, value, and affordability. We conducted cost, cost-effectiveness, and budget impact analyses of Mobile Link using cost and outcomes data from the Mobile Link trial and other sources. For the cost analysis, we estimated the total, per-person, and incremental costs of Mobile Link compared with usual care. Using probabilistic decision-analytic models, we estimated the 1-year cost-effectiveness of Mobile Link from payer and combined payer and patient perspectives by converting selected primary and secondary outcomes from the trial to disability-adjusted life years (DALYs) averted. Finally, we estimated the financial costs of scaling up Mobile Link's messaging and outreach services to 70% of female entertainment workers in 5 years. The incremental costs of Mobile Link were US $199 from a payer perspective and US $195 per person from a combined payer and patient perspective. With an average of 0.018 (95% predicted interval -0.088 to 0.126) DALYs averted, Mobile Link's cost-effectiveness was US $10,955 per DALY from a payer perspective (US $10,755 per DALY averted from a payer and patient perspective). The costs of Mobile Link would have to decrease by 85%, or its effectiveness would have to be 5.56 times higher, for the intervention to meet the upper limit of recommended cost-effectiveness thresholds in Cambodia (US $1671 per DALY averted). The 5-year cost of scaling Mobile Link to 34,790 female entertainment workers was estimated at US $1.64 million or US $46 per person per year. This study provided a comprehensive economic evaluation of Mobile Link. We found that Mobile Link is not likely to be cost-effective unless its costs decrease or its effectiveness increases. Scaling up Mobile Link to more female entertainment workers is estimated to cost less than the costs of the trial. Given the importance of linking female entertainment workers to essential services, future research should focus on enhancing the effectiveness of Mobile Link or developing new mobile health interventions for this population. ClinicalTrials.gov NCT03117842; https://clinicaltrials.gov/study/NCT03117842.