The incident happened after 5 a.m. Friday in a construction zone east of Exit 358 approaching the bridge that spans the Delaware River into New Jersey.
Officials tell Action News the tractor-trailer was carrying printers' ink when it caught fire.
Firefighters were able to contain the fire to the truck. No serious injuries were reported.
But the fire caused ink to spill on parts of the highway. Hazardous materials crews were called to the scene.
All eastbound lanes of the turnpike were closed as police investigated and crews worked to clear the road of spilled ink and other material.
Eastbound traffic was being detoured off the turnpike at the Delaware Valley exit until about 8:30 a.m.
After that, the Pennsylvania Turnpike Authority declared a Plan X road closure, and traffic was detoured off the highway farther west, at the U.S. 1 exit in Bensalem, Pa.
The detour remained in effect until about 2:15 p.m. Friday, when all lanes of the turnpike reopened.