Roberts, 21, and Overstreet, 23, started dating after meeting at Coachella, California, in 2011. They broke up in January and then reunited in April, reported Daily Telegraph.
"They're done. The last few weeks have been really rough," a source said.
The couple were last seen together at the Nylon Young Hollywood party on May 9 but they were already experiencing trouble.
"They posed for pictures. After that, the two were on opposite sides of the VIP section. It's a really immature relationship. All they did was fight. They're just on two different paths in life. They just grew apart and decided to part ways," the source added.