Rallies by neo-Nazis and white nationalists in Charlottesville, Virginia, in August led to violent street clashes with counter-protesters.
After the melee, as counter-protesters were dispersing, a 20-year-old man who is said by law enforcement to have harboured Nazi sympathies smashed his car into the crowd, killing a 32-year-old woman.
“This executive order is an additional step to ensure that the University of Florida and the entire community is prepared so everyone can stay safe,” Governor Scott said in a statement.
Governor Scott said in the order there was a need to implement a coordinated security plan among local and state agencies before the speech by Richard Spencer on Thursday in Gainesville.
Mr Spencer heads a white nationalist group
University of Florida officials were not immediately available for comment. Local media reports said the school was threatened with a lawsuit if it tried to block Spencer.
The Orlando Sentinel quoted Spencer as saying the emergency declaration was “flattering” but “most likely overkill.”
In a video message this week, University of Florida President Kent Fuchs told students to stay away, deny Spencer attention and ignore his “message of hate.”
“The values of our universities are not shared by Mr Spencer. Our campuses are places where people from all races, origins and religions are welcome and treated with love,” he said, adding he was required by law to allow him speak.
“We refuse to be defined by this event. We will overcome this external threat to our campus and our values,” Mr Fuchs said.