The amendments will require companies to have targets for the number of women on their boards and in executive positions and disclose the actual number of women in those roles.
Companies will also need to provide annual disclosure regarding director term limits and other renewal mechanisms and policies regarding the representation of women.
The new rules are set to take effect on Dec. 31.
The provinces included in the changes are Ontario, Quebec, Manitoba, Saskatchewan, New Brunswick, Newfoundland and Labrador and Nova Scotia.
The Northwest Territories and Nunavut have also signed on.
The Ontario Securities Commission said the changes are intended to increase transparency for investors regarding the representation of women on boards of directors and in senior management.
"We know from stakeholder and investor feedback in the participating jurisdictions that this issue is an important one, and we've taken steps in a co-ordinated fashion to broaden disclosure in this area," OSC chairman and chief executive Howard Wetston said in a statement.