Eugen Rosenstock-Huessy's work related to andragogy is insufficiently discussed in adult pedagogical literature, although most of his work deals with this field, if we employ his own definition of andragogy. This paper makes visible his role as an andragogical pioneer, and clarifies his understanding of andragogy and basic perspectives in his andragogical approach. Rosenstock-Huessy was a leading force in the first theoretical, academic reflections on adult pedagogical issues in the 1920s, and he implemented his thoughts and ideas in different practical actions. He became a source of inspiration for adult educators in the inter-war and post-war period. A comparison with two central figures within adult education, Eduard Lindeman and Malcolm Knowles, is also included in this paper. (Contains 13 notes.)