Leptospirosis, a globally re-emerging zoonotic illness, presents significant challenges to public health, particularly in tropical and subtropical regions. Environmental and social factors contribute to its spread, with outbreaks frequently associated with flooding and natural disasters. The disease, caused by the pathogen Leptospira, is traditionally linked to various animal hosts and is now observed in both tropical and temperate climates. While leptospirosis is commonly underestimated and underreported, its impact on human and animal health is substantial. This chapter investigates the role of swine as potential reservoirs for human infections with leptospirosis. Swine, among various animal species, harbor Leptospira asymptomatically, shedding the bacteria into the environment. The intensification and expansion of swine farming contribute to disseminating Leptospira globally. Additionally, wild pig populations serve as reservoirs for various serovars, posing risks to human health through environmental contamination. Understanding the epidemiology, transmission dynamics, and pathogenesis of leptospirosis is crucial for effective prevention and control strategies. One Health approach, emphasizing the interconnectedness of human, animal, and environmental health, are essential for mitigating the spread of leptospirosis. Furthermore, social, and occupational factors, such as agricultural practices and inadequate sanitation, significantly influence the transmission of leptospires. This chapter explores the complex interplay between swine, humans, and the environment in transmitting leptospirosis, highlighting the importance of interdisciplinary collaboration and comprehensive surveillance efforts in addressing this global public health concern.