Deterioration of water quality is a serious problem that continues to face the environment due to the discharge of untreated wastewater into water bodies. The present systematic review and meta-analysis research evaluated the efficacy of micro/nano bubbles (MNB) in the treatment of polluted effluents in relation to BOD and COD. The research was of quantitative approach, applied type and non-experimental design. The scientific articles were collected from Scopus and Web of Science databases from the period of January 2011 to November 2021. The results showed that only five investigations were included and subjected to meta-analysis. Those studies indicated that treatment with MNBs achieved removals between 69 to 100% and 68 to 99% for BOD5 and COD, respectively. The best removal efficiency (97% COD and 100% BOD5) was achieved in the scientific investigation of Rameshkumar (Rameshkumar et al. 2019). Finally, it is concluded that MNBs effectively reduce the pollutants present in wastewater.