Spurrier left Florida after the 2001 season to coach the NFL's Washington Redskins for two seasons, and is currently in his 11th season as head coach of the South Carolina Gamecocks.
Spurrier is credited with giving Gainesville's Ben Hill Griffin stadium its nickname, "The Swamp" in the early 1990's, famously describing it as a place where "only Gators get out alive."
The 1966 Heisman Trophy winner finished his 12-year run as Gators head coach with a 122-27-1 record, making him the school's all-time winningest coach.
The 70-year-old coach informed his players Monday night. The person spoke to The Associated Press on condition of anonymity because South Carolina has not publicly announced Spurrier's decision.
The person says the school has not named an interim coach but likely would announce someone to finish out the season by Wednesday.
The Gamecocks are 2-4 and 0-4 in the Southeastern Conference for the first time in Spurrier's 23 seasons coaching in the league at Florida and South Carolina.
After news spread of Spurrier's retirement, many took to social media to congratulate and thank the legendary coach, including several notable former Florida players.
Spurrier did not return messages from the AP seeking comment.