Fire department spokeswoman Dana Vander Houwen said it was reported about 4 a.m. Friday near the intersection of 85th and Greenwood.
The roof partially collapsed, forcing firefighters to take defensive positions outside to prevent the flames from spreading.
Vander Houwen said there are no reports of injuries, other than a firefighter who is being treated for a twisted ankle.
The building is owned by the Taproot Theatre, but the organization's facilities were not seriously damaged.
"We've got a firewall between the theater and the restaurants next door," said Mark Lund, the group's production and design manager.
Lund said he was called by his alarm company reporting that a door alarm had gone off, and he drove to the building assuming it was a false alarm.
"As I turned on the side street I saw the flames," he said. "The four restaurants were all on fire."
It appears the fire started in one of the restaurants and then spread to three others.
Lisa Etter-Carlson said he rushed to the scene in her pajamas.
"Saw smoke billowing -- we could see from half a mile away, "she said. "Just wept, thinking about the business owners and the community here."
Etter-Carlson worked at what was the Greenbean Coffeehouse -- a popular community gathering spot in the building.
"It was very difficult to watch a place you love so much (go down in flames)," she said.
The fire was under control by about 6 a.m., but all that remains is charred debris.
Phung Hoang stood in shock, staring at what remained of her family's Szechuan Bistro.
"I just couldn't believe it that the business is completely gone," she said. "What am I going to do next?"
Each of the lost business has a story.
The Pho Tic Tac Restaurant was another family business. The owners of the Teriyaki and Wok had just bought it six weeks ago.
Scott Nolte, who owns the building and the neighboring Taproot Theatre, was devastated, seeing the building riddled with smoke and water damage.
"Your livelihood is gone. You go home to feed the family and your place of work is gone. It's just not there," he said. "We want it back. We just don't want it to be a black hole in the middle of such a vibrant block."
Officials with PAWS said 11 cats were moved from their Cat City adoption center a few doors down from the burned restaurants to their main shelter in Lynnwood as a precaution. None of the cats was injured. (Find out how to adopt one of the cats)
The cause of the fire has not been determined, and fire officials, citing safety issues, said they won't be able to enter the charred, old structure for days to begin investigating.
The Taproot Theatre said it will move the weekend performances of its current production to the Seattle Children's Theatre due to water damage in the lobby of the Taproot.