Crews used ladders and ropes to rescue those inside the restaurant, reportedly including former Cincinnati Bengals star Cris Collinsworth.
Authorities say Jeff Ruby's Waterfront restaurant drifted about 100 yards from the dock. A bridge stopped the restaurant from floating down the river any further.
The river had recently risen above flood stage after severe winter storms.
The National Weather Service said a flood warning was in effect for the Ohio River at Cincinnati next to Covington with the river at 4 a.m. local time at 55.3 feet - or 3.3 feet above flood stage.
The Associated Press contributed to this report.