Eugene Buechel (Eugen Büchel), * October 20, 1874 in Schleida, now Schleid, in Thuringia, Germany, † October 27, 1954 in O'Neill, Nebraska, United States, was a Roman Catholic priest and missionary, linguist and anthropologist among the Brulé or Sicangu Lakota or Sioux on the Rosebud Indian Reservation and the related Oglala Lakota or Sioux on the Pine Ridge Indian Reservation in South Dakota.