Cal Dunlap, the Reno lawyer representing the woman, confirmed the settlement on Friday but declined to discuss the terms of the agreement.
"The matter has been resolved and I have no further comment," he told The Associated Press.
The Reno Gazette-Journal first reported the settlement on its website. It also dismisses claims against Harrah's employees whom the woman had accused of covering up the alleged sexual assault in Roethlisberger's penthouse suite in July 2008.
Dunlap first told Washoe District Court Judge Brent Adams in papers filed last Nov. 30 that his client wanted to have a stay lifted so the case could be dismissed because a settlement was pending.
"All parties have reached a resolution of all claims and counterclaims," he wrote.
Adams formally dismissed the case Dec. 27 but neither side had publicized it until now.
David Cornwell, Roethlisberger's lawyer, and Ryan Tollner, his agent, did not immediately return telephone calls seeking comment on Friday.
The Nevada Supreme Court had ruled against the two-time Super Bowl champion quarterback's request in August to have the case moved from Reno to Carson City because it was closer to where the alleged incident had occurred at Harrah's in Stateline.
The woman was a VIP casino hostess at Harrah's when she said Roethlisberger allegedly lured her to his room under the pretense of fixing his television. Roethlisberger was in town at the time to play in a celebrity golf tournament.
Roethlisberger denied the allegations.
The original lawsuit filed in 2009 sought a minimum of $440,000 in damages from the quarterback, at least $50,000 in damages from the Harrah's officials and an unspecified amount in punitive damages.
The woman said she never filed a criminal complaint because she feared Harrah's would side with Roethlisberger and she would be fired.