Netflix’s “13 Reasons Why” is too “dangerous” for kids, according to a posh private school on the Upper West Side that sent home a detailed warning to parents about the controversial new show.

Administration at Stephen Gaynor School on W. 90th Street sent out the parental advisory “to share our concerns and offer some advice” after students began buzzing about the hit show, Radar Online reported Friday.

The series follows high school student Hannah Baker, who kills herself and leaves behind cassette recordings for the 13 people she blames for her suicide.

It’s come under fire for depicting Baker’s suicide in a graphic scene in the final episode, which included a warning for viewers beforehand.

The more than $60,000-a-year school urged parents to “consider whether your teen is ready to watch a series as intense as ‘13 Reasons Why,’ which is actually rated TV-MA for mature audiences,” according to the letter obtained by Radar.

“This miniseries attempts to address many themes that can lead to important conversations with students; however, aspects of the miniseries go against the recommendations of mental health professionals and suicide prevention models,” the letter said.

It concludes by saying, “We do not recommend that your teen watches the series, however, if your teen is going to watch the series, we encourage you to watch it together and to discuss your reactions. If your teen has already watched the series, it is still important to discuss the issues raised in the series.”

The school — which counts the spawn of morning TV host Kelly Ripa and ex-Viacom CEO Tom Freston as students — didn’t immediately return a message seeking comment.

Response to the first season of the Selena Gomez-produced show has been polarizing after it premiered March 31, with critics slamming it for glamorizing suicide.

“The show actually doesn’t present a viable alternative to suicide. The show doesn’t talk about mental illness or depression, doesn’t name those words,” said Dan Reidenberg, the executive director for Suicide Awareness Voices of Education, according to ABC News. “My thoughts about the series are that it’s probably done more harm than any good.”

But fans have praised the show, which is based off Jay Asher’s 2007 novel, for tackling heated issues affecting teens, including bullying, drug use and sex.

The show’s screenwriter and creator Brian Yorkey said they took care in portraying Baker’s suicide.

“We worked very hard not to be gratuitous, but we did want it to be painful to watch because we wanted it to be very clear that there is nothing, in any way, worthwhile about suicide,” Yorkey told Entertainment Weekly last week.

Additional reporting by Selim Algar