Perfluorooctane sulfonate (PFOS) stands as a silent yet potent environmental contaminant with far-reaching implications for both human health and the broader ecosystem. This chapter provides a comprehensive overview of PFOS, highlighting its distinct chemical characteristics, its pervasive presence in the environment, and the resulting health and ecological issues it presents. As an extensively utilized industrial chemical, PFOS’s ubiquitous distribution has raised pressing concerns, especially given its persistent nature and potential adverse effects on diverse organisms. The review delves deep into the global pathways of PFOS contamination, elucidating its varied sources, potential health repercussions, and its profound impact on aquatic and terrestrial life. Regulatory measures, both at international and national levels, are critically examined, underscoring the pivotal role of policy interventions in curbing PFOS emissions and usage. While significant strides have been made in detection, remediation, and policy frameworks, the chapter emphasizes the persistent knowledge gaps and the ensuing need for collaborative, interdisciplinary research. As we navigate the complexities of PFOS, it becomes evident that a concerted global response, underpinned by scientific insights and technological advancements, is paramount to effectively address this silent threat and ensure a sustainable future for all.