An MTA conductor was punched in the face after he asked a 17-year-old to stop smoking pot on a Manhattan subway Monday afternoon, police said.

The teen was toking on a southbound 6 train at the 103rd Street and Lexington Avenue station around 12:30 p.m. when the conductor asked him to stop.

That’s when the teen socked the train worker hard enough to cut his left eye, cops said.

The conductor, whose name wasn’t released, was taken to Mount Sinai Hospital in stable condition, cops said.

The teen, whose name also wasn’t released, was charged with felony assault.