Christine Elliott already has support from several members of her party's caucus in her quest for Progressive Conservative leadership.
She announced her plans to run on Wednesday, one week before current leader Tim Hudak will officially resign from the post.
Newstalk 1010 learned of her plans on Tuesday.
"After many discussions with my sons, John, Galen, and Quinn, my friends and my family, I am determined to lead the Progressive Conservative Party of Ontario," she said.
Elliot says she doesn't think the key to gaining support is moving the party closer to the political centre but rather finding a way to connect with voters.
She says voters sent the party a message on June 12, when the PCs lost nine seats, that it failed to connect with the issues that matter.
The Whitby-Oshawa MPP, and deputy leader, spoke across the street from Queen's Park, standing at a podium with a sign that read, "Christine, Ready To Lead."
When pressed if she was too nice to effectively lead the party, Elliott stresses she's tough. She pointed specifically to the months after the death of her husband, former federal finance minister Jim Flaherty in the spring.
Elliott says he would have backed her decision to do this, since he had supported the idea back when she rain in 2009.
Hudak won that one, with Elliott placing third.