Extremophiles, microorganisms adapted to thrive in extreme environments, offer innovative pathways for sustainable municipal waste management. Their unique metabolic processes enable efficient degradation and transformation of various municipal waste products, including organic waste, industrial pollutants, and heavy metals, under conditions where mesophilic microorganisms fail. This chapter examines the potential of extremophiles in municipal waste management, with a focus on waste-to-energy conversion, bioremediation, and pollutant degradation. Key groups such as thermophiles, halophiles, acidophiles, alkaliphiles, and metalophiles demonstrate applications ranging from bioenergy production through anaerobic digestion to the detoxification of hazardous compounds. The chapter also highlights how extremophiles contribute to reducing landfill dependency, enhancing resource recovery, and supporting a circular economy. Additionally, challenges and future directions for extremophile-based solutions in municipal waste management are discussed, emphasizing the transformative impact of these organisms on sustainable urban waste systems.