The presumptive Democratic nominee earned 47 percent support in the new poll vs. Trump at 39 percent. In early May, Clinton and Trump were locked in a virtual tie.
The change comes after Clinton became the presumptive nominee earlier this month, while Trump's campaign has stumbled in recent weeks.
Trump has lost ground in the Sunshine State among men, nonwhites and independents. His 13-point lead among men in early May has shrunk to a statistically insignificant 4 points.
Meanwhile, Clinton has grown her lead among nonwhites to 57 points from 43 points. Clinton also leads independents by 9 points after running even with Trump last month.
Other Quinnipiac polls in Ohio and Pennsylvania show a tight race. Clinton and Trump are tied at 40 percent in Ohio. In Pennsylvania, typically a reliable Democratic state that Trump hopes will tip his way, Clinton earned 42 percent vs. Trump at 41 percent.
Nationally, Hillary Clinton continues to hold an advantage. A new CNN-ORC poll released this morning shows Clinton with a slim lead over Trump, 47 percent vs. 42 percent. But other recent polling out since Clinton locked up the nomination has shown a statistically significant lead.