This review highlights the significant interaction between microplastic (MP) pollution and its impact on wastewater treatment systems, focusing on optimizing biogas production. We explore various sources of MPs, including tire-derived MPs, and their introduction into wastewater environments. This review delves into the mechanical and physicochemical challenges MPs pose in treatment processes, emphasizing the need for comprehensive mitigation strategies. The biological effects of MPs on microbial consortia essential for biogas production are analyzed, particularly how these pollutants interfere with each stage of anaerobic digestion—hydrolysis, acidogenesis, acetogenesis, and methanogenesis—and, consequently, biogas generation. We examine MPs’ quantitative and qualitative impacts on biogas output and production rates, uncovering how MPs disrupt microbial activity in these stages. This review also discusses novel mitigation strategies combining different sludge pretreatment methods with MPs. Our goal is to enhance the sustainability of wastewater management by promoting efficient biogas production and environmental protection in the presence of persistent MP contamination.