The fire broke out at a four-story building in the 1400-block of North Wells Street at about 11:51 p.m., police said.
Everyone made it out of the building, with two people being transported to a hospital in fair condition for smoke inhalation and a third transported with a possible ankle injury, police said.
Connor Weston, who lives on the fourth floor, said his pet is missing.
"I don't know where my cat is at," Weston said. "They kicked out both of our doors actually, the rear and the main entrance. My bathroom is almost destroyed.
The cause of the fire is under investigation.