Ottawa–Rideau was a short lived provincial electoral district in Ottawa, Ontario.

It elected one member to the Legislative Assembly of Ontario.

[1] The riding included all of pre-amalgamation Ottawa south of Walkley Road south of Baseline Road.

It also included part of the city of Nepean northeast of this line: Black Rapids Creek to Woodroffe Avenue to CN railway to Merivale Road.

The riding elected two members of the Legislative Assembly: Yvonne O'Neill, a Liberal from 1987 to 1995 and then Garry Guzzo, a Progressive Conservative from 1995 to 1999.