The elite Dalton School has a new motto, according to court documents: Out of sight, out of mind.

The exclusive Manhattan prep school — where actor Chevy Chase and journalist Anderson Cooper studied — is trying to duck a lawsuit by a former student who says she was sexually assaulted by the headmaster, arguing that it can’t be sued in a New Jersey court because the school’s located in New York.

“Dalton has no substantial affiliation with New Jersey,” the school’s attorneys claim in court papers.

The victim, identified as J.S., was 14 years old when Dalton’s headmaster Gardner Dunnan allegedly groped her at his Manhattan apartment and his New Jersey summer home in 1986 and 1987.

She brought the suit in the Garden State, where the statute of limitations is more flexible than laws governing sexual abuse in New York.

“Dalton argues this court has no jurisdiction over it,” Mariann Wang, attorney for the now 46-year-old former student says in a response filed in federal court Wednesday.

“Yet its 14-year-old charge would not have been sexually assaulted but for Dalton,” Wang says.

Her client, “J.S. suffered as she did only because the man who embodied, represented and led Dalton for nearly a quarter century was empowered to commit the abuse,” Wang says.

J.S. lived with Dunnan’s family while attending the E. 89th Street school tuition-free — in exchange for working as a “family helper.”

Dunnan was forced to resign as headmaster of storied prep school in 1997 — after 23 years — for an affair with a married teacher.

He has not answered the suit, but his attorney said he “vehemently denies these allegations.”

A Dalton spokeswoman said, “As this is ongoing litigation we feel it is not appropriate for us to comment at this time.”