"Thinking of You" is a song written and recorded by American singer and songwriter Katy Perry from her second studio album, One of the Boys (2008). It was produced by Katy Perry and Butch Walker, and released on January 12, 2009, as the album's third single. "Thinking of You" deals with a break-up in which Perry does not want to move on but has no choice, and feels nostalgic of a previous lover while in a relationship with another man. Retrospectively, "Thinking of You" has been described as a favorite among her fans.

Katheryn Elizabeth Hudson, known professionally as Katy Perry, is an American singer, songwriter, and television personality. She is known for her influence on modern pop music and her camp style, being dubbed the "Queen of Camp" by Vogue and Rolling Stone. At 16, Perry released a gospel record titled Katy Hudson (2001) under Red Hill Records, which was commercially unsuccessful. She moved to Los Angeles at 17 to venture into secular music, and later adopted the stage name "Katy Perry" from her mother's maiden name. She recorded an album while signed to Columbia Records, but was dropped before signing to Capitol Records.