In March 1962 an outbreak of prolonged, uncontrollable laughter began at the Missionary Girls’ School in the village of Kashasha on the shores of Lake Victoria in northern Tanganyika. It started with three pupils and within days spread to dozens of students; over time the phenomenon reached neighboring villages and affected hundreds of people, primarily schoolgirls and young women. The episodes included laughter, crying, fainting, respiratory problems and general inability to attend classes; some schools closed and students were sent home. The outbreak persisted in waves for several months and is frequently cited in medical and social-science literature as a clear, early example of mass psychogenic illness (MPI), sometimes called mass sociogenic illness. Contemporary investigators and later researchers documented several recurring features consistent with MPI: a clear social network among those affected (schoolmates and communities connected by family and friendship), rapid spread in the absence of an identifiable pathogen or toxin, predominance among adolescent females, and symptoms that were transient and resolved without specific biomedical treatment. Social and cultural context played a central role in explanations. Tanganyika had recently achieved independence (1961), and communities were experiencing social stress, shifts in authority and schooling, and economic uncertainty. Scholars have emphasized how stress, anxiety about rapid social change, and close-knit institutional settings like boarding schools can create conditions in which functional neurological symptoms spread socially. Important details about the event are well documented but interpreted in different ways. Medical teams who examined patients found no consistent physiological cause; laboratory tests and clinical examinations did not identify an infectious agent. Anthropologists and historians, reviewing archived reports and interviewing participants years later, have analyzed the episode as an interaction of psychological stress, suggestion, and local cultural understandings of illness and behavior. Some accounts emphasize playful or attention-seeking behavior that escalated, while others stress genuine distress and involuntary symptoms among those affected. The designation “epidemic” in this case refers to the rapid social transmission of symptoms rather than infectious disease. The Tanganyika laughing episode influenced later research into MPI and contributed to the modern conceptual framework distinguishing mass psychogenic illness from infectious outbreaks. It is often taught in public-health, psychiatry and anthropology courses as an instructive case showing how symptoms can propagate through social networks and how public-health responses must address social context, communication and reassurance rather than searching solely for a biological cause. Subsequent comparable outbreaks—ranging from fainting spells in schools to alleged chemical exposures—have echoed similar patterns. Limitations and caveats: precise case counts and a single unified timeline vary across reports; many contemporary records were produced by missionaries, colonial administrators and early post-colonial officials whose perspectives shaped the documentation. Oral histories collected later can differ in emphasis and detail. While the Tanganyika laughing episode is widely referenced as a documented MPI event, interpretations about its causes remain partly inferential rather than definitively proven. Legacy: the episode remains an important historical example for understanding how psychological, social and cultural factors interact in public-health phenomena. It continues to be cited in literature on mass psychogenic illness, and its study has informed guidelines for outbreak investigation that incorporate sociocultural analysis alongside clinical and laboratory evaluation.