A woman had accused Winston of sexually assaulting her in his off-campus apartment in December 2012.
"The preponderance of the evidence has not shown that you are responsible for any of the charge violations of the Code," Major Harding, a former Florida State Supreme Court Chief Justice who oversaw the case, said in a letter to the parties obtained by the Associated Press and USA Today. "Namely, I find that the evidence before me is insufficient to satisfy the burden of proof."
"This was a complex case, and I worked hard to make sure both parties had a full and fair opportunity to present information," Harding said in the statement.
During the conduct hearing held earlier this December, Winston declined to answer questions about whether he sexually assaulted the woman, a former FSU student, but did read a five-page statement in which he detailed his account of the events on the night of Dec. 7, 2012 and declared his innocence.
At the hearing, Winston repeatedly declined to answer questions from Harding and during cross-examination by his accuser, according to people familiar with the case.
The accuser has until Jan. 13 to appeal the ruling.
Winston and the undefeated Seminoles (No. 3 CFP, No. 2 AP) will next play Oregon (No. 2 CFP, No. 3 AP) in the Rose Bowl Game Presented By Northwestern Mutual on New Year's Day on ESPN.
Information from ESPN.com's Mark Schlabach and The Associated Press contributed to this report.