Intermittent freezing rain is predicted overnight from Alqonquin Park to Upper Gatineau and the Pontiac.
Precipitation is approaching the area from the west, according to Environment Canada.
"Light rain mixed with a little wet snow or ice pellets will overspread the regions late this afternoon and early this evening, then quickly change to freezing rain in most places as temperatures fall to near or just below the freezing mark," the weather agency said on its website.
No warnings were posted for Ottawa as of 4 p.m. Saturday, but warnings were issued for Upper Gatineau and the Pontiac in Quebec, as well as Renfrew, Pembroke, Petawawa, Barry's Bay, Algonquin Park, Deep River and Arnprior in Eastern Ontario.
The precipitation is expected to change to occasional rain by Sunday morning, the weather agency said.
Anywhere from two to five millimetres of ice accumulation is possible in affected areas. Motorists are urged to use caution.