"I Knew You Were Trouble" is a song by the American singer-songwriter Taylor Swift from her fourth studio album, Red (2012). Swift wrote the song with its producers, Max Martin and Shellback. A dance-pop, pop rock, and teen pop song with a dubstep refrain, "I Knew You Were Trouble" features electric guitars and synthesizers, with lyrics that talk about self-blame after a toxic relationship. The dubstep production divided music critics, who noted it as a radical move from Swift's previous country pop songs.

Taylor Alison Swift is an American singer-songwriter. A subject of widespread public interest with a vast fanbase, she has influenced the music industry, popular culture, and politics through her songwriting, artistry, entrepreneurship, and advocacy.