Introduction: Patients with COVID-19 often suffer from psychological problems such as post-traumatic stress disorder (PTSD) and self-stigmatization that may negatively impact their quality of life and sleep. This study examined mental health as a potential mediating factor linking self-stigmatization and PTSD to quality of life and sleep. Methods: Using a cross-sectional design, 844 people who had recovered from COVID-19 were called and interviewed. Data were collected using structured scales. Structural equation modeling was applied to assess fitness of a mediation model including self-stigma and PTSD as independent factors and quality of life and insomnia as dependent variables. Results: Mental health, COVID-19-related self-stigma, and mental quality of life were associated. Insomnia, PTSD, and COVID-19-related self-stigma displayed significant direct associations (r =.334 to 0.454; p <.01). A mediation model indicated satisfactory goodness of fit (CFI = 0.968, TLI = 0.950, SRMR = 0.071, RMSEA = 0.068). Mental health as a mediator had negative relationships with COVID-19-related self-stigma, PTSD, and insomnia and positive associations with quality of life. Conclusion: Mental health may mediate effects of COVID-19-related self-stigma and PTSD on quality of life and insomnia. Designing programs to improve mental health among patients with COVID-19 may include efforts to reduce negative effects of PTSD and COVID-19-related self-stigma on quality of life and insomnia.