A teen clocked a fellow straphanger in the face with a skateboard during a fight on a Midtown subway platform, cops said Monday.

The violent encounter started at 5:45 p.m. Sunday while the two were riding the R train in Manhattan, according to police.

At one point, Shiair Barber, 19, turned to the other man and asked, “what are you looking at?”

The two started fighting, and the altercation spilled out onto the subway platform at E. 59th Street and Lexington Avenue — where Barber allegedly punched the 27-year-old victim in the face, then grabbed a skateboard from another rider and hit the man with it, cops said.

The man was taken to Brookdale for minor injuries.

Barber was arrested and charged with assault, according to police.