It happened around 1:55 a.m. in the area of Route 1 and Old Lincoln Highway in Bensalem.
Investigators say the pedestrian was trying to cross Route 1 when the incident occurred.
The vehicle, a 2006 white box truck, remained at the scene.
The pedestrian was taken to the hospital in critical condition.
Police say alcohol or drugs do not appear to be factors in this crash.
Anyone with information should contact Officer Neil Tropiano at 215-633-3719.