Background and Objective: Female migrant domestic workers (MDW), approximately 8.5 million globally, often live in their employer’s home under vulnerable conditions. In Hong Kong, MDWs currently comprise 5% of the population. This study was conducted to assess the association between employment conditions and mental health, and the mediating roles stress and job satisfaction have, among female MDWs in Hong Kong. Methods: Participants completed an online cross-sectional survey. A total of 1,965 survey were collected between August 2020 and August 2021. Questions in the survey were related to MDWs Background: information, employment conditions, stress, job satisfaction, and two mental health outcomes: anxiety (General Anxiety Disorder-7) and depression (Patient Health Questionnaire-9). An employment conditions score was created to assess the cumulative effect poor employment conditions had on mental health. A multicategorical parallel mediation analysis was used to assess the direct effect employment conditions have on mental health and the indirect effects through stress and job satisfaction. Results: Overall, 17.7% of MDWs were reported to be suffering from anxiety and 30.8% from depression. An increase in poor employment conditions was statistically significantly associated with an increase in both outcomes, while stress levels and job satisfaction mediated this association. Conclusions: The findings call for increased scrutiny of employment conditions and mental wellbeing of MDWs.