The victim, identified as a man in his 50's, was fatally struck on the midfield service road Romeo around 5 a.m.
Police say the man had some sort of medical issue or lost control of the truck and fell out of it.
"The incident appears to be a single operator accident, meaning no other vehicles were involved, where the driver of a ground service equipment vehicle either had a medical issue or lost control of the vehicle," LAX spokeswoman Katherine Alvarado said in a statement.
The vehicle reportedly came to a stop near the LAFD Station 80. Responding firefighters found the man unconscious. He was pronounced dead at the scene by paramedics.
No further details were released.
The accident remains under investigation. No flights were impacted by the incident.
His name withheld pending notification of kin.
DEVELOPING: We will add more details to this report as they become available.