Kamen Rider Ryuki (Japanese: 仮面ライダー龍騎, Hepburn: Kamen Raidā Ryūki, lit. 'Masked Rider Dragon Knight', stylized in English as Masked Rider Ryuki) is a Japanese tokusatsu television series. The twelfth installment in the Kamen Rider Series, it was a joint collaboration between Ishimori Productions and Toei, and it was shown on TV Asahi from February 3, 2002 to January 19, 2003. The series marked the franchise's switch from Columbia Music Entertainment to Avex Group, which continues to produce music for the series today. The series aired along with Ninpu Sentai Hurricanger. It is the first series debuted an animal, knights, cards, and battle royal motif.

In 2008, Ryuki was adapted into the American television series Kamen Rider: Dragon Knight, the second American adaptation of a Kamen Rider series after Saban's Masked Rider (1995).