The couple, who have been dating off and on for more than a year, reportedly split up after Aniston returned home from Europe where she was promoting her family movie "Marley & Me," while Mayer remained in Los Angeles working on his music. The two made headlines when they together attended last month's Oscars ceremony where Aniston's ex-husband Brad Pitt and his new girlfriend, Angelina Jolie, were both nominees.
"They had some disagreements and decided to not continue to see each other," one source close to Aniston and Mayer told People magazine. "Jen is moving on with her life like she always does. She seems happy."
A second insider said Mayer dumped Aniston after she returned from Europe.
The magazine said Aniston's and Mayer's publicists declined to comment on its story.