On 7 May 1966, an episode began at a secondary school in the village of Kashasha, near Bukoba in what was then Tanganyika (now northern Tanzania). A schoolgirl fainted during class; within hours the symptom spread to dozens of classmates and then to girls at neighboring schools. Reported manifestations included fainting, trembling, crying, shouting, and hyperventilation. The event attracted local officials, medical workers and investigators from the newly independent Tanganyikan government, and later became a key case in the medical literature on mass psychogenic illness (MPI). Contemporaneous accounts and later clinical reports emphasized the rapid onset and apparent social transmission of symptoms without consistent organic findings. Medical examinations generally found no infectious cause or toxic exposure that could account for the pattern. Instead, clinicians and anthropologists identified psychosocial factors: high levels of stress among students, recent political and social change after independence (Tanganyika gained independence in 1961), anxiety about examinations and school discipline, and local cultural beliefs that shaped expression of distress. Investigators also noted gender dynamics—most affected were adolescent girls living and studying away from home—and that symptoms tended to begin in one individual and spread through close social networks. The Kashasha episode was quickly cited in both African public-health reports and international psychiatric literature. It became an influential example because it combined clear documentation, rapid diffusion among a defined population, and the absence of a biological agent. Researchers used the case to illustrate concepts now central to understanding MPI: symptomatic contagion via sight and suggestion, the role of social stressors and expectations, and culturally patterned symptom expression. Subsequent fieldwork and follow-up studies in East Africa compared this event with other school-based outbreaks and emphasized that such episodes are not arbitrary ‘‘mass hysteria’’ but typically meaningful social responses to pressure and uncertainty. Historians and clinicians caution against pejorative or dismissive labels. Modern commentary frames the Kashasha outbreak within a biopsychosocial model: psychological distress expressed through physical symptoms in a social context that enables rapid transmission. Some later analyses critique early reports for insufficient attention to local voices or for interpreting symptoms primarily through Western psychiatric categories. Others underscore the event’s role in developing public-health responses that prioritize calm communication, community engagement, and psychosocial support rather than coercive medical interventions. The Kashasha incident remains an often-cited, well-documented early case of mass psychogenic illness in the postcolonial African context. It informed approaches to similar outbreaks worldwide: rapid assessment to exclude toxic or infectious causes, attention to social networks and stressors, culturally sensitive communication, and steps to reduce suggestibility (for example, temporary regrouping of affected populations and restoring normal routines). While debates persist about terminology and interpretation, the 1966 Tanganyika schoolgirls’ outbreak is historically significant for showing how collective distress can manifest physically and spread in tightly connected communities.