Karel Bernard Boedijn (29 June 1893 – 29 August 1964) was a Dutch botanist and mycologist. Born in Amsterdam, he graduated with a PhD from the University of Amsterdam in 1925; his thesis was titled "Der Zusammenhang zwischen den Chromosomen und Mutationen bei Oenothera lamarckiana" (The relationship between chromosomes and mutations in Oenothera lamarckiana).
Many species as well as narrower and broader taxonomical units have been named for Boedijn.