Due to their on-screen-chemistry, rumours had it that in 2003 Barton dated The OC-costar Benjamin McKenzie. However this was denied equally, fans assumed that they didn't let it out, due to the fact that Barton was 17, McKenzie 24 years old, which if they would've admitted their romance, would have made him liable to prosecution.

In February 2004, Barton announced she dated oil heir Brandon Davis, grandson of Marvin Davis. Their relationship ended in July 2005. From 2005 to 2007 she was in a relationship with Whitestarr lead singer, and ex of Kimberly Stewart, Cisco Adler. They separated in 2007 when nude pictures of Adler began to circulate on the internet. At the end of 2007 there were rumours of a brief fling with actor, model and musician Jamie Dornan, after the two were seen leaving an Arcade Fire gig together in Brixton, London, but Barton has always denied they pursued a relationship. Barton is currently dating Rooney guitarist Taylor Locke (who appeared with his band o