Silver Lake last week appointed Rebecca Prain to its board, while Chalice this week appointed Linda Kenyon.
According to the Australian Institute of Company Directors, there were 28 all-male boards in 2015 when it began monitoring gender diversity.
"This is an historical milestone for Australia that should be celebrated," AICD CEO and managing director Angus Armour said.
"A great shift in the approach to diversity by our largest organisations has occurred in recent years.
"This is testament to the leadership and commitment of ASX chairs and directors, as well as the numerous groups who have pushed for change and ensured that gender diversity remains a priority for organisations.
"We want to ensure this success is maintained. It is important all chairs to continue to prioritise diversity in the search for directors."
Australia is one of few countries to achieve 30% women on the boards of its top companies without mandated quotas or government intervention, according to the recent Towards Board Gender Parity report by the University of Queensland Business School.
"When the push for gender diversity on the ASX 200 began, there was a view that Australia did not offer the talent pool of qualified women to achieve the targets we set," 30% Club Australia chair Nicola Wakefield Evans said.
"With nearly 500 ASX 200 board positions now held by women, that myth is well and truly busted - the calibre of women on our leading boards is exceedingly high, from those who are well established to emerging directors achieving their first listed role."
The diversity milestone was welcomed by the Australian Council of Superannuation Investors.
In 2010, when ACSI began its efforts to improve board gender diversity, only 8% of ASX 200 director seats were occupied by women. In 2015, when ACSI set 30% as a minimum objective, there were 34 companies in the ASX 200 without a woman director.
This week, 126 companies in the ASX 200 have 30% or more women on their boards, with an average of 34% women. Women now comprise more than half of directors on the boards of 15 companies in the ASX 200.
"The benefits of having more women in governance roles are well established and are being clearly recognised in boardrooms around Australia," ACSI CEO Louise Davidson said.
"More diverse boards make for better governed companies, which is intrinsically linked to long-term shareholder value.
"It's important that we maintain the momentum for change and continue to increase both the number of women, and diversity of experience on boards.
The AICD is working with the 30% Club Australia and other key stakeholders to ensure gender balance on all listed boards, to focus the pipeline of women leaders and this continued trajectory of improvement and to look at wider diversity on boards.
The AICD and ACSI support a 40:40:20 model of gender balance, whereby at least 40% of director seats are held by both men and women on a consistent basis, with flexibility over the remaining 20% of seats.
"Listed companies should set a time frame within which they will achieve gender balance on their boards," Davidson said.
