Here are some of Trump's comments about Mexico in this election:
When he announced his candidacy in June 2015, Trump immediately criticized politicians for letting Mexico "beat" the United States economically and established a harsh tone on immigration. His comments on Mexican immigrants themselves raised the most eyebrows.
"When Mexico sends its people, they're not sending their best. … They're sending people that have a lot of problems, and they're bringing those problems with us. They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."
In the same speech, Trump called for a wall on the U.S.-Mexico border, a key proposal for his campaign. He has pledged to make Mexico pay for it.
"Mexico's going to pay for the wall," he said at the GOP debate hosted by CNBC last October. "I love the Mexican people. I respect the Mexican leaders, but their leaders are much sharper, much smarter and more cunning than our leader."
Pena Nieto previously told a Mexican newspaper that there was "no scenario" under which it would pay for a wall.
Trump has criticized U.S. District Judge Gonzalo Curiel, who is presiding over a lawsuit against Trump University, for bias because of his Mexican heritage.
"I'm building a wall. It's an inherent conflict of interest," Trump told The Wall Street Journal in June.
He received criticism from both sides of the political aisle, and House Speaker Paul Ryan called it the "textbook definition" of a racist comment.
Trump has repeatedly bashed the North American Free Trade Agreement, the 1990s deal that opened trade with Canada and Mexico. He called NAFTA the "worst trade deal" in U.S. history and has pledged to renegotiate it.