"Passion" is a song by Hikaru Utada, released in Japan as a single on December 14, 2005. It was used as the theme song for the Disney Interactive Studios/Square Enix game Kingdom Hearts II in Japan, while an English version also sung by Utada, titled "Sanctuary", was used for the international release of the game.

In an interview, Utada said, "It's like... as if 'Hikari' was the dawn, and 'Passion' has a concluding or 'dusk' feeling to it. The lyrics of 'Passion' show how phases of the past, present and future of the character in my song relate to each other."

During her 2010 international tour, Utada: In the Flesh 2010, Utada combined "Passion" with "Sanctuary", alternating between the Japanese and English versions of the songs.

"Passion" was performed during Utada's two date concert series Wild Life in December 2010.

British rapper Devlin sampled "Passion (After the Battle)" on his song "London City" from his 2010 album Bud, Sweat and Beers.