Mrs Trump said her husband would make a "fantastic president"
Donald Trump's wife has vowed to focus on combating online bullying particularly against children if she becomes first lady.
In a rare campaign speech, Melania Trump said she would work as an advocate for women and children.
Her comments come as her husband is accused of sexual harassment by a string of women and also faces claims that he is a bully, including by presidential rival Hillary Clinton.
Mrs Trump said: "Our culture has gotten too mean and too rough, especially to children and teenagers."
And she said it's "absolutely unacceptable" when children are mocked, bullied and attacked online anonymously.
She said it would be an "honour and privilege" to serve as first lady and her husband would make a "fantastic president".
The Slovenia-born former model made the rare appearance on the campaign trail near Philadelphia as she tried to persuade Americans to vote for the billionaire businessman next Tuesday.
She said her husband has a "deep love and respect for the US" and has pledged to "restore integrity to Washington and respect for America abroad".
Mrs Trump described her decision to move to the US and eventually get citizenship "as the greatest privilege in the world".
Her last speech, at the Republican National Convention, was initially well-received but was later overshadowed by claims that sections were copied from First Lady Michelle Obama's address to the 2008 Democratic Convention.
Mrs Trump has been largely absent from the campaign, and has said her priority is raising the couple's 10-year-old son, Barron.
Earlier in the day, Mr Trump "stayed on script" rather than going "off-message" as he rallied supporters in Florida ahead of Tuesday's presidential election.
The Republican candidate read from an autocue and rarely spoke off the cuff in an apparent attempt to stay gaffe-free.
It is believed his poll numbers go down when he is caught up in a scandal or a controversy, like when he previously made sexist comments on tape about women.
At the rally in Jacksonville, Mr Trump again criticised Democratic opponent Mrs Clinton calling her "crooked" and claiming she should not be allowed to run for the White House.
And he slammed Barack Obama, saying the President should be working in the White House rather than on the campaign trail drumming up support for Mrs Clinton.
Mr Trump again criticised his rival over her emails, saying she "created an email server to shield and guard her activities. So simple".
He claimed Mrs Clinton "lied to the FBI and the American people", as a new FBI investigation was launched last week into emails that may be connected to her private server.
Mr Trump said she should not become president as it would "create an unprecedented constitutional crisis", adding she was "likely to be under investigation for many years" and it was "likely to conclude in a criminal trial".