"You can say what you want, but if they had guns -- if our people had guns, if they were allowed to carry -- it would have been a much, much different situation," he said to thunderous applause from the audience in Beaumont, Texas.
"When you look at Paris, you know, the toughest gun laws in the world, nobody had guns except for the bad guys, nobody," he said. "Nobody had guns, and they were just shooting them one by one."
The real estate mogul, who is battling Ben Carson atop the polls for the GOP nomination, opened his speech today with a moment of silence for the victims in last night's attack, calling it "horrible" and "terrible to watch."
Trump also hit President Obama over his comments to ABC News on Thursday that ISIS was "contained."
He also linked the incident to the United States taking in Syrian refugees, although he indicated the U.S. was going to take in 250,000, but the Obama administration has said 10,000 would be taken in the next fiscal year.
"And we all have heart, and we all want people taken care of and all of that, but with the problems our country has, to take in 250,000 people -- some of whom are going to have problems, big problems -- is just insane," he said. "You have to be insane. Terrible."
ABC's John Santucci and Michael Falcone contributed to this report.