Donald Trump would win by a landslide if American teenagers got to choose the next president, according to a new poll.

A solid 47.1 percent of high school students backed Trump while only 32.6 percent voted for Hillary Clinton in a recent online mock election, according to After School, the country’s largest teen-focused social network. Trump also trounced Clinton in 42 of 50 states, according to the poll, in which 106,608 teens voted from Oct. 14-21 by using an app.

After School organizers told The Post they were surprised by the results but believe it shows the Selfie Generation loves The Donald because he’s a “political outsider” who shares teens’ “anti-establishment” values.

Other reasons students gave for why they support Trump included: “He is going to lower taxes” and “He’s not Hillary.”

Overall, Trump won all 11 swing states that he is banking on to win the presidency, as well as New York, which is a stronghold with registered Democratic voters.

However, Clinton won the teen vote in New York City — capturing every borough but Staten Island.

In an odd twist, Trump also raked in more votes than Clinton among high school girls, even though the poll came out a week after the leaking of the infamous 2005 Hollywood Access tape — in which he bragged about grabbing women “by the p—y.” Trump still earned 40 percent of the teen girl vote while Clinton took 38 percent.

‘The mock election results would have been far different had Bernie Sanders been in the running. He connected extremely well with teens.’ - Jeff Collins, vice president of After School

Trump may have also beat Clinton because teens believe he’s more like Bernie Sanders — the real first choice among American youth— said Jeff Collins, vice president of After School, a non-partisan group.

“The mock election results would have been far different had Bernie Sanders been in the running. He connected extremely well with teens, who considered him to be the real ‘outsider,’ who offered hope for progress on issues most important to them — from climate change to student loan debt,” Collins said.

Some teens also rallied behind third-party candidates like Libertarian Gary Johnson, who earned 11.9 percent of the vote, and Green Party candidate Jill Stein, who garnered 8.5 percent.

Trump cheered the results Tuesday, saying in an email, “What a great honor. Nobody is more important to the future of our country. Young people want change- they get it!”

The Clinton campaign did not return a request for comment.

After School conducted its poll through an online “Election Center” set up with help from partners DoSomething.org and Countable.us to help educate teens on the presidential candidates and issues. Voting was done by 13- to 19-year-olds through After School’s app.

Online polls are notoriously easy to manipulate, but safeguards were put in place to ensure high school teens only voted once.

Although the mock election lacked the strict rules or social science of standard political opinion polls, Collins said the results still provide a “great snapshot” into the minds of America’s teens.

After School is used by millions of students covering more than 80 percent of the America’s high schools. It is apolitical but supports many progressive causes close to Clinton’s heart, such as equality for lesbian, gay, bisexual and transgender people, Collins said.

Of those who cast votes, 37,348 teens reported favoring Republican values, 26,028 claimed to be future Democrats, another 34,020 listed no political affiliation and the rest backed the Libertarian or Green parties.