Officers went to a home in north Portland home Tuesday at 5 p.m. local time after getting a report that Lok Marcellay had disappeared.
Detectives say they have no information to indicate a stranger abducted Lok, according to The Oregonian.
The case is reminiscent of that of Kyron Hormon, now 8, who's been missing since attending a school science fair at his school in Portland on June 4.
Investigators from the Missing Persons Unit searched for Lok throughout the night, to no avail, says the newspaper.
Lok is described as being 4-feet-7 inches tall, weighing about 80 pounds, with straight black shoulder length hair and brown eyes
He was wearing an orange T-shirt, khaki cargo shorts and thick, black-framed glasses when he was last seen, Portland police spokesman Sgt. Pete Simpson told The Oregonian.
Matt Shelby, spokesman for Portland Public Schools, told the paper Lok is in fourth grade at Astor Elementary School in North Portland. Shelby said the bus driver confirmed that he boarded the bus and got off at his regular stop in front of his home.
Simpson told The Oregonian detectives don't believe Lok was taken by a stranger, so they waited until after noon Wednesday to alert the media.
Lok also goes by the last name Marcellay-Ball, or just Ball, the newspaper says.