She had a McNugget in her hand, a gun to her head, and no fear in her heart.

A Harlem teen protected her fast food with her quick hands, smacking the weapon away to end an armed hold-up try inside a Manhattan subway station, cops said Thursday.

The 13-year-old was first approached inside a McDonald’s on E. 103rd St. and Third Ave., where a 12-year-old schoolmate asked for one of her chicken nuggets, according to cops.

When the girl said no Tuesday, the angry boy tracked her to the 103rd St. subway station on Lexington Ave. — where 20 minutes later, he pulled what appeared to be a gun and pointed it at her head, police said. When he again demanded a McNugget, the teen smacked the gun away from her head and instructed the suspect to leave her alone. Both then boarded the No. 6 train when it reached the station, and the victim allegedly saw the suspect show his gun to another kid.

She reported the incident to school officials on Wednesday afternoon, and the suspect was later arrested for the attempted robbery of the McNugget.

The gun was not found and the suspect’s case was referred to Family Court.