"I Knew You Were Trouble" is a song by American singer-songwriter Taylor Swift from her fourth studio album, Red (2012). Co-written by Swift, Max Martin and Shellback and produced by Martin and Shellback, Swift goes full pop with the song for a mainstream appeal. The song was released on October 9, 2012 by Big Machine Records as the third promotional single from her Red album. In the song, Swift shares her feelings with her fans by describing her frustration of knowing a boy who would break her heart before getting together. When romance runs aground, it can feel like the end of the world. Sure, she knows she brought that trouble on herself. She should have known better. She did know better. But she courted love from a dangerous beau anyway.

The song's music video (directed by Anthony Mandler) premiered on December 13, 2012 on MTV as part of the channel's week long celebration for the singer's birthday. Taylor's love interest in the video is played by Reeve Carney who starred in Spider-Man: Turn Off the Dark as Peter Parker/Spider-Man.

"I Knew You Were Trouble" received generally positive reviews and good commercial success. The single generated strong digital sales and debuted at number three on the Billboard Hot 100. It sold more than 400K copies within its first week, making it Swift's 14th entry in the top ten.

"I Knew You Were Trouble" lyrics:

Once upon a time, a few mistakes ago

I was in your sights, you got me alone

You found me, you found me

You found me-e-e-e-e

I guess you didn't care and I guess I liked that

And when I fell hard, you took a step back

Without me, without me

Without me-e-e-e-e

And he's long gone

When he's next to me

And I realize, the blame is on me

'Cause I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Till you put me down

Oh I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Now I'm lying on the cold hard ground

Oh, oh, trouble, trouble, trouble

Oh, oh, trouble, trouble, trouble

No apologies, he'll never see you cry

Pretends he doesn't know that he's the reason why

You're drowning, you're drowning

You're drowning-ing-ing-ing-ing

And I heard you moved on from whispers on the street

A new notch in your belt is all I'll ever be

Now I see, Now I see

Now I see-e-e-e-e

He was long gone

When he met me

And I realize the joke is on me

Hey!

I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Till you put me down

Oh I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Now I'm lying on the cold hard ground

Oh, Oh, trouble, trouble, trouble

Oh, Oh, trouble, trouble, trouble

And the saddest fear...

Comes creeping in...

That you never loved me... or her or anyone or anything

Yeah!

I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Till you put me down

Oh I knew you were trouble when you walked in

So shame on me now, flew me to places I'd never been

Now I'm lying on the cold hard ground

Oh, Oh, trouble, trouble, trouble

Oh, Oh, trouble, trouble, trouble

I knew you were trouble when you walked in

Trouble, trouble, trouble

I knew you were trouble when you walked in

Trouble, trouble, trouble!