Donna J. Kossy (born May 18, 1957) is a US writer, zine publisher, and online used book dealer based in Portland, Oregon. Specializing in the history of "forgotten, discredited and extreme ideas", which she calls "crackpotology and kookology", she is better known for her books Kooks: A Guide to the Outer Limits of Human Belief (1994, featuring the first biography of Francis E. Dec) and Strange Creations: Aberrant Ideas of Human Origins from Ancient Astronauts to Aquatic Apes (2001). Kossy was also the founder and curator of the Kooks Museum (1996–1999, online), and the editor-publisher of the magazine Book Happy (1997–2002, about "weird and obscure books").

Described by Wired as "an expert on kooks [who] has a genuine, if sometimes uncomfortable, affection for her subjects", Kossy wrote books reviewed in publications ranging from Fortean Times to New Scientist. Journalist Jonathan Vankin named her "the unchallenged authority on, well, kooks", and writer Bruce Sterling noted that she "boldly blazes new trails in the vast intellectual wilderness of American writers, thinkers and philosophers who were or are completely nuts".