A man was slashed in the neck outside Port Authority in Hell’s Kitchen, police said.

The 18-year-old victim was attacked on West 42nd Street, between Eighth and Ninth avenues, around 11:30 p.m. Sunday, across from the bus terminal, cops said.

The injured man was rushed to Bellevue Hospital, where he was expected to survive.

Investigators aren’t sure what sparked the attack outside Kaufman’s Army & Navy store, and it wasn’t immediately clear if the two men knew each other.

The suspect fled toward Ninth Avenue and was last seen wearing a red jacket and blue jeans. He is 5 feet 5.