The sale, held Saturday on polo grounds in Santa Barbara, took up three tents and had items from her homes in Hawaii, Indiana and California, People magazine reported.
Among some of the pricier items on hand were autographed electric scooters, a 19th-century doll expected to fetch $8,000 and a Louis XVI chest of drawers worth up to $50,000, the magazine said.
Winfrey said there would be many dolls at the sale.
"People come to stay with me, and they say they get scared with all the dolls," she said. "You wake up, and there's like 12 dolls staring at you."
Funds raised from the yard sale are expected to go to Lady O's Leadership Academy for Girls in South Africa.
"I'm trying not to be attached to things," she said. "I'm trying to live the life that I talk about, like not letting things define you. But it's hard."