Heat stroke represents a spectrum of pathophysiological conditions progressing from heat illness to heat exhaustion, thereby encompassing central nervous system dysfunction, multi-organ failure, and metabolic disturbances leading to morbidity and mortality. Heat illness and heat stroke continue to be a formidable challenge not only for the civilian population but also for the military and paramilitary operations in India. Heat-related illnesses represent a spectrum of disorders that include minor heat cramps, heat exhaustion, and life-threatening heat stroke. While the human body tightly regulates core temperature through physiological mechanisms that include alterations in blood circulation and regulation of evaporative heat loss through sweating, extreme temperatures override these regulatory mechanisms. During high heat stress index, the core body temperature rises above 40°C resulting in the involvement of multiple organ systems and triggering pathophysiological mechanisms of heat illness. Depending on its cause, heat stroke could be non-exertional/classic heat stroke due to climatic factors and heat waves, or exertional, resulting from exercise and dehydration. The pathophysiology of heat stroke involves a complex interplay of thermoregulatory and cardiovascular factors, leading to catastrophic systemic inflammatory response, eventually causing multi-organ failure. The clinical diagnosis of heat stroke is extremely important and is primarily based on the triad syndrome, viz., evidence of hyperthermia, CNS alterations, and history of exposure to environmental heat. Despite advancements in understanding heat stroke, effective treatment strategies for its management and treatment are still obscure. A comprehensive multistep prevention protocol could assist in preventing the symptoms associated with heat stroke. Effective preventive and mitigation strategies are also required to make the susceptible populations aware of heat-related illnesses.