A teen shot his ex-girlfriend dead inside his Long Island home Wednesday before turning the gun on himself — and surviving, according to authorities.

The unidentified 17-year-old gunned down his ex-girlfriend, Emily Finn, 18, inside his home in Nesconset around 11:10 a.m. on Wednesday, the Suffolk County Police Department said in a statement.

The teen boy then shot himself in the face, cops said.

A police officer and another man stand near cars parked in a yard.An unidentified 17-year-old fatally shot his ex-girlfriend, Emily Finn, 18, inside his Nesconset home before turning the gun on himself. James Messerschmidt

His parents called 911 after the shots rang out, according to police.

Finn, who had just graduated from Sayville High School in June,was tragically pronounced dead on the scene, police said.

She had gone to her ex-boyfriend’s home to return some of his belongings following their recent breakup, Suffolk County Det. Lt. Kevin Beyrer, commanding officer of the department’s homicide bureau, confirmed to Greater Long Island.

The 17-year-old boy was taken to Stony Brook University Hospital in critical but stable condition, authorities added.

He will be charged with second-degree murder and arraigned at a later date, cops said.

Suffolk County police vehicles with flashing lights and officers at a scene.Finn was pronounced dead on the scene, and the 17-year-old was taken to the hospital in critical but stable condition. James Messerschmidt

There was no “domestic history” between the teens or 911 calls at the Nesconset house, involving Finn or the gunman, police said at the scene, according to the outlet. 

A neighbor told The Post that the teen’s family was a “typical” household and involved with the community.

“They’re just a great, typical community-involved family. They’re a normal family, and now multiple families will be destroyed by this,” the resident, who wished not to be identified, said. 

Another neighbor, who did not know the family personally,  was shocked to hear of the incident occurring so close to home and on the day before Thanksgiving. 

“It’s terrible. It’s sad, and you never think it will hit so close to home. It’s crazy,” the neighbor said. 

The investigation remains ongoing, and a motive is not yet clear.