Pamela Wang from Kealakekua on Big Island was out walking when she saw the 5.2lb (2.35kg) fruit. "It was as big as my head," she told the West Hawaii Today newspaper.
Ms Wang has submitted an application to Guinness World Records. In 2009 a 4.8lb avocado was verified in Venezuela.
"Smashed avocado" on toast has become a popular breakfast among young people in the West.
It has come to symbolise a generational wealth divides after an Australian columnist lambasted young people worried about high property prices for spending money on the dish instead of saving.
Ms Wang said her giant avocado came from a 40-year-old tree that overhangs a street she regularly walks along. In Hawaii, fruit that overhangs or falls in a public place is free to claim.
She provided photographs of the avocado to West Hawaii Today.
Guinness's verification process requires the fruit to be photographed and weighed in the presence of an expert - in this case Ken Love, a farmer and head of the organisation Hawaii Tropical Fruit Growers.
"I've seen [avocados] longer and I've seen them fatter, but not both," Mr Love told West Hawaii Today.
"I think people have other ones that they don't weigh, but I think this one, it was way up there," he added.
Ms Wang is due to hear back from Guinness within two months.
She ate the massive avocado with friends after the weigh-in.
"It tasted excellent. The tree is very good. We had 10 people there and didn't even use up half of one half of the avocado," she said.
The local area has recorded several other heaviest fruit, Mr Love told West Hawaii Today.
Local farmers currently hold world records for the heaviest jackfruit and soursop, a fruit that occurs in the American tropics, and a local farmer also once held the record for the heaviest mango, he said.