The "That Awkward Moment" actor, 26, and the "Fast & Furious" actress, 36, called it quits after two months of playing together in "Lifestyles of the Rich and Famous" locales, Us Weekly reported Wednesday.
They reportedly ended it after having a blowout fight in Ibiza, Spain, sources told the magazine.
"Michelle is going to do her own thing. Zac knew this about her when he got with her," one source said, adding that he was still into her while she was done with him.
The unexpected couple -- she was hooking up with 22-year-old model Cara Delevingne before she and Efron were linked -- had been photographed kissing on a boat off the coast of Italy in early July, making out on the dance floor at an Ibiza nightclub a few weeks later and dining with friends in early August.
Efron, who's now back in town filming "We Are Your Friends," has dabbled in much cooler pursuits since the split: He did the Ice Bucket Challenge on Tuesday with Ashley Tisdale, not flinching too much at the moment of truth but noting that the experience was "way colder than anticipated."