Red King may refer to:
Red king crab, a species of king crab
The red King playing card
Red King (Ultra monster), a foe of the Japanese superhero Ultraman
Red King (comics), a number of comics characters of the same name
William II of England, commonly known as William "Rufus", or "The Red King"
Rory "Red King" MacDonald, a Canadian MMA fighter
The Red King (novel), a children's book by author Victor Kelleher
The Red King (TV series), a 2024 British crime drama television series
Red King (Through the Looking-Glass), a character in the Lewis Carroll novel Through the Looking-Glass
Lal Baadshah (lit. 'Red King'), a 1999 Indian Hindi-language film
An ancient king whose descendants are the main characters in Children of the Red King series of books by Jenny Nimmo
Another name for the Crimson King from the works of Stephen King