John Kennedy Marshall (November 12, 1932 – April 22, 2005) was an American anthropologist and acclaimed documentary filmmaker best known for his work in Namibia recording the lives of the Ju/'hoansi (also called the !Kung Bushmen).

Marshall first traveled to the Kalahari Desert and met the Ju/'hoansi of the Nyae Nyae area in 1949 on a trip initiated by his father. Throughout the 1950s and 1960's members of the Marshall family returned to the Kalahari Desert numerous times to conduct an ethnographic study of the Ju/'hoansi. From 1950-1958 Marshall filmed the hunting and gathering life of the Ju/'hoansi. His first edited film, The Hunters, was released in 1957 and was an almost instant classic of ethnographic film.

During the 1960s and 1970s, Marshall produced many short films about the Ju/'hoansi of Nyae Nyae and pursued other film projects in the United States. He was the cinematographer and co-director for Fred Wiseman's first documentary film, Titicut Follies. In 1968-1969, he shot, edited and directed the ground-breaking Pittsburgh Police series of short films. In 1968, Marshall and Tim Asch founded Documentary Educational Resources, a non-profit organization dedicated to facilitating the use of cross-cultural documentaries in the classroom.

Marshall became involved in grassroots organizing and development in Nyae Nyae in the 1980s, forming a foundation that would become the Nyae Nyae Development Foundation of Namibia and devoting himself to advocating on behalf of the Ju/'hoansi. In 2003, the Society for Visual Anthropology bestowed on Marshall a lifetime achievement award for his work among the hunter gatherer society.

Marshall's documentary footage and edited films and videos of Ju/'hoansi are held at the Human Studies Film Archives, Smithsonian Institution. Known officially as the John Marshall Ju/'hoan Bushman Film and Video Collection, 1950–2000, the collection was added to UNESCO's Memory of the World Register for documentary heritage of world importance in July 2009.