Two teenagers were among three New Yorkers gunned down across the Big Apple Sunday night in a pair of deadly shootings, according to authorities.

Two victims, including an 18-year-old woman, were fatally struck by gunfire in Harlem before a 17-year-old boy was shot and killed in Brooklyn about 20 minutes later, police said.

When cops reached the scene of the first shooting around 7:27 p.m., they found Ashley Ballard, 18, with gunshot wounds to the back and head, and 25-year-old Harry Mendoza shot in the head near East 128th Street and Lexington Avenue, the NYPD said.

Both were rushed to Harlem Hospital where Ballard, of East Harlem, was pronounced dead shortly after 8 p.m.

Mendoza, of Upper Manhattan, was initially listed in critical condition, but later died of his wounds at around 10 p.m., cops said.

It’s unclear what the relationship was between the two Manhattan victims and whether they were intended targets.

Gunshots then struck 17-year-old Bryan Henriquez in the neck and torso near 256 East 37th St. in Brooklyn at around 7:45 p.m., the NYPD said.

The Flatbush resident was taken by EMS to Kings County Hospital where he was pronounced dead.

No motive was immediately known in either shooting as the investigations were ongoing.

No arrests have been made.

Additional reporting by Steven Vago and Larry Celona.