Suspect X (容疑者Xの献身, Yōgisha Ekkusu no Kenshin) is a 2008 Japanese mystery-thriller film based on the novel, The Devotion of Suspect X, directed by Hiroshi Nishitani. The film was a continuation of the popular Japanese serial drama Galileo and included the same cast. It topped Japan's box office for four consecutive weeks and was the third-highest-grossing Japanese movie in 2008. The soundtrack was released on October 1, 2008. Suspect X was the first of several film adaptations of The Devotion of Suspect X, followed by film adaptations such as Perfect Number (2012) from South Korea and Kolaigaran (2019) and Jaane Jaan (2023) from India.