Aim: This review aimed to synthesise the evidence related to the incidence of serious and non-serious adverse events with the use of monoclonal antibodies (mAbs) among COVID-19 patients. Methods: Databases were searched from January 2020 to September 2023 for randomized clinical trials (RCTs) that used mAbs for the treatment of COVID-19 regardless of disease severity. Study screening, data extraction, and data analysis were done independently by two reviewers. The Cochrane risk of bias 1.0 tool was used for methodological quality assessment. Results: Twenty-three studies were identified for analysis with 20,099 participants in the treatment arm and 20191 participants in the controlled arm. Seven trials reported hepatoxicity and there was a statistically significant increase in the chance of hepatoxicity among patients treated with mAbs compared to those given standard of care (SoC) or placebo with RR = 1.70, 95% CI 1.29 – 2.24. Five trials reported neutropenia and there was a statistically significant association of neutropenia with the use of mAbs compared to SoC or placebo with RR = 4.03, 95% CI 1.74- 9.34. Ten trials reported any disease-related serious adverse events related to disease and there was a reduction of risk compared to SoC/placebo, but was not statistically significant (RR = 0.88, 95% CI 0.70-1.11). Conclusion: The use of mAbs was found to be associated with an increased risk of hepatoxicity and neutropenia compared to SoC/placebo among COVID-19 patients with moderate certainty of evidence. Long-term observational studies are recommended to observe post-COVID adverse events related to mAbs.