Adolf Ellegard Jensen (1 January 1899 – 20 May 1965) was one of the most important German ethnologists of the first half of the 20th century.

Jensen's main research interests were myth, ritual and cult. He furthered the theory of Cultural Morphology founded by Leo Frobenius. Jensen is mostly known for his research on religious sacrifice that led him to the introduction of the concept of Dema Deity. His best-known work is 'Myth and Cult Among Primitive Peoples', published in 1951.

Jensen studied physics in Kiel and in Bonn, concluding his studies with a dissertation on Max Planck and Ernst Mach in 1922. One year later he became acquainted with Leo Frobenius and became his faithful disciple. As a member of the Institute for Cultural Morphology founded by Frobenius and known today as Frobenius Institute, Jensen took part in research journeys to South Africa, Libya, Southern Ethiopia and Seram Island in the Moluccas. He became a full-time ethnologist after publishing a paper on circumcision and rite of passage ceremonies. He held a teaching position at the University of Frankfurt beginning in 1925.