Delius most often refers to Frederick Delius, an English composer.
Delius may also mean:
Delius (surname), a list of people and a fictional character Delius Glacier, Alexander Island, Antarctica, named after the composer An epithet of the ancient Greek and Roman god Apollo "Delius (Song of Summer)", a song from the 1980 Kate Bush album Never for Ever
See also Pristimantis delius, a South American frog species