The source is not authorized to discuss the split with the press and spoke on condition of anonymity.
The breakup apparently happened last week. Distance and their busy schedules were cited as factors.
Eighteen-year-old Bieber is touring to promote his latest album, "Believe," which contains the hit "Boyfriend." Twenty-year-old Gomez is filming a "Wizards of Waverly Place" reunion for the Disney Channel.
The pair made their relationship public in February 2011.
Bieber seems to be doing OK, at least publicly. On the red carpet of Wednesday's Victoria's Secret fashion show he said, "I'd rather be here than anywhere in the world."