Kelsie Brown Harder (August 23, 1922 – April 9, 2007) was an American professor and onomastician.

After serving in the United States Army after World War II, he earned a bachelor's degree and master's degree in English from Vanderbilt University, then a Ph.D. from University of Florida.

Starting his career at Youngstown State University, he joined SUNY Potsdam in 1964.

During his long career at SUNY Potsdam he nurtured the talents of younger writers, "in particular the novelist T. Coreghessan Boyle and poet Allen Hoey.

He served as director of the Place Name Survey of the United States, and in 1990 gave the keynote address at the Library of Congress on the 100th anniversary of the United States Board on Geographic Names.