Police made the discovery shortly after 12:20 a.m., after a fire alarm sounded at the Tower 1 dorm and someone called 911 about a person with a gun there, school spokesman Grant Heston said on CNN's "Starting Point with Soledad O'Brien." Officers entered the dorm and found a male dead of a self-inflicted gunshot wound in a bedroom, Heston said.
Police also found a handgun, an assault weapon and a bag of improvised explosive devices in the room, Heston said.
The Orange County Sheriff's Office and the FBI are assisting the UCF Police Department with the investigation. The Sheriff's Office's bomb squad is on campus to examine the IEDs found at the scene, UCF said.
Heston didn't say whether the dead person was a student, nor did he release a name.
The dorm, home to about 500 students, was evacuated.
"The safety of our students in Tower 1 and our entire campus community is our top priority," UCF Police Chief Richard Beary said.
UCF said it was providing the evacuated students counseling and food at the university's Veterans Academic Resource Center.
The parking garage closest to Tower 1 was initially closed off, but the university reopened it around 9 a.m.
UCF has more than 59,000 students at its main campus and 10 regional campuses, according to the school.
CNN's Marlena Baldacci contributed to this report.