Cyanobacteria, ancient and photosynthetically active microorganisms, are gaining attention as powerful agents in environmental bioremediation due to their diverse metabolic pathways and ecological adaptability. This chapter provides a comprehensive overview of the mechanisms, applications, and future prospects of cyanobacteria in remediating polluted environments. It explores how cyanobacteria contribute to nutrient removal, heavy metal sequestration, organic pollutant degradation, and carbon capture all essential processes in restoring the health and functionality of aquatic and terrestrial ecosystems. The chapter also highlights their role in environmental restoration efforts, including wastewater treatment, soil rehabilitation, recovery of eutrophic water bodies, and oil spill remediation. Innovative approaches such as genetic engineering, immobilization techniques, and integrated bioremediation systems are examined to showcase how technological advancements are improving the efficiency and scalability of cyanobacterial applications. Furthermore, future research directions emphasize the need for climate-resilient strains, large-scale deployment strategies, and supportive policy frameworks to overcome existing challenges like toxin production and environmental variability. The chapter concludes that cyanobacteria offer a sustainable, low-cost, and multifunctional solution for environmental cleanup and resource recovery. When aligned with eco-engineering principles and circular economy goals, their potential can be fully harnessed to support global environmental sustainability and climate resilience.