The group Friends of Oakley had been collecting the items in barrels located throughout town and planned to distribute them to an estimated 300 families in need, said Pat Anderson, vice president of the charity's board.
Around 3 p.m. Tuesday, volunteers arriving for an afternoon gift-wrapping event discovered that a large amount of food, clothes and toys was missing from barrels stored at Almond Grove Elementary School.
Someone had stolen most of the toys stored there and some food, Oakley police said.
"It's devastating and it's upsetting, and I can't believe it's happened," Anderson said.
She said that in past years, the organization has stored its donations in a different location but switched this year to the local elementary school.
This year, residents began dropping donations into barrels throughout Oakley just before Thanksgiving.
The donation drive is set to continue through Dec. 18, when volunteers will distribute the donated food and gifts to the families who have registered to receive them.
Each year on the weekend before Christmas, dozens of community volunteers pack boxes full of food, blankets and clothing and wrap gifts, Anderson said.
"It's a fabulous community and they always do great things -- we just ran into some people who didn't do any good," she said.
Donation barrels can be found at Oakley City Hall, in front of the organization's office at 2063 Main St. and in front of several schools and small businesses in town.
Anderson said more information about the drive can be found at www.friendsofoakley.com.