The Pacific Tsunami Warning Center in Hawaii said there was no widespread tsunami generated from the shallow quake that occurred at 7:19 a.m. local time.
Brandon Aydlett, a forecaster at the National Weather Service's office in Guam, said nothing was felt in the U.S. territory.
"It was completely unnoticed out here," he said.
Shawn Gumataotao, deputy chief of staff for Gov. Felix Camacho, said there were no immediate reports of damage with many people sleeping through the quake.
Officials in nearby Commonwealth of the Northern Mariana Islands, also said there were no reports of damage.
The temblor occurred at a depth of about 3 miles, according to the U.S. Geological Survey.
Guam is located 3,700 miles southwest of Hawaii.