Background: The long-term impact of COVID-19 is still unknown. This study aimed to explore post COVID-19 effects on patients chest computed tomography (CT), lung function, respiratory symptoms, fatigue, functional capacity, health-related quality of life (HRQoL), and the ability to return to work beyond 3 months post infection. Methods: A systematic search was performed on PubMed, Web of Science, and Ovid MEDLINE on 22 May 2021, to identify studies that reported persistent effects of COVID-19 beyond 3 months follow-up. Data on the proportion of patients who had the outcome were collected and analyzed using a one-group meta-analysis. Results: Data were extracted from 24 articles that presented information on a total of 5323 adults, post-infection, between 3 to 6 months after symptom onset or hospital discharge. The pooled prevalence of CT abnormalities was 59% (95% CI 44–73, I2 = 96%), abnormal lung function was 39% (95% CI 24–55, I2 = 94%), fatigue was 38% (95% CI 27–49, I2 = 98%), dyspnea was 32% (95% CI 24–40, I2 = 98%), chest paint/tightness was 16% (95% CI 12–21, I2 = 94%), and cough was 13%, (95% CI 9–17, I2 = 94%). Decreased functional capacity and HRQoL were found in 36% (95% CI 22–49, I2 = 97%) and 52% (95% CI 33–71, I2 = 94%), respectively. On average, 8 out of 10 of the patients had returned to work or reported no work impairment. Conclusion: Post-COVID-19 patients may experience persistent respiratory symptoms, fatigue, decreased functional capacity and decreased quality of life up to 6 months after infection. Further studies are needed to establish the extent to which post-COVID-19 effects continue beyond 6 months, how they interact with each other, and to clarify their causes and their effective management.