The incident happened in the afternoon on a major road in Antipas municipality in North Cotabato province on the second-largest island of Mindanao.
Thirteen bodies were recovered from the scene, fire officer Samuel Lumayon told AFP, but he warned the death toll could rise after a number of seriously injured people were taken to hospital.
Witnesses reported that the brakes of the truck appeared to fail before the collision happened, disaster official Mic Garfin told AFP.
Garfin said the van caught fire, possibly because of the impact of the crash.
Deadly road accidents are common in the Philippines, where drivers frequently flout the rules and vehicles are often poorly maintained or overloaded.