Elliott has been the member of the legislature for Whitby-Oshawa, a riding east of Toronto, since she won a 2006 byelection. A lawyer who practised real estate, corporate and estate law, she graduated from London's University of Western Ontario.
Elliott ran against Hudak for the party leadership in 2009 and finished third. Her then-colleague Frank Klees came in second.
Her message is expected to be that Ontario PCs have not been listening, were rejected by voters, and need to fix that.
Hudak is expected to step down as of July 2.
Elliott is the first to officially declare her intention to run.