Membrane bioreactor (MBR) has become a credible alternative to conventional treatment technology especially for water reuse and to enhance the removal of micropollutants from municipal wastewater. Numerous large-scale MBR plants have been commissioned over the last few years. In general, MBR can produce better effluent in terms of both basic water quality and concentration of micropollutants than conventional wastewater treatment processes. Micropollutant removal from the liquid phase by MBR is governed mostly by biodegradation and adsorption to sludge. Factors governing these removal mechanisms include physicochemical properties of the micropollutant (e.g., hydrophobicity and molecular structure), configuration of the biological process, and operating parameters (e.g., pH, temperature, solid retention time, and dissolved oxygen concentration or redox condition). A notable research gap in the current literature is the lack of insight into the microbial community of the biological reactor. With molecular biology research tools such as next-generation sequencing becoming more accessible to water researchers, techniques to regulate the microbial community to enhance micropollutant removal by MBR can be expected in the near future.