Firms will have to report how many women they employ in senior jobs under reforms unveiled by the government on Thursday.
Legislation due to come into force in a year's time will make it easier for shareholders to hold companies to account, said ministers.
Following recommendations from a recent review by Lord Davies, firms will have to say how many women are employed in total as well as in senior posts.
Table showing the top 20 countries by percentage of leadership roles - Source: SHL
Business Minister Jo Swinson said the move would encourage greater diversity in firms and drive a culture change at the heart of business.
Other changes include cutting "clutter" from annual reports to make it easier for shareholders to find out how a company was performing.
The minister said: "It's widely acknowledged that the UK leads the world in standards of annual reporting, and that those standards are rising every year. However, over a period of years reports have become longer, more complex and increasingly difficult for shareholders to navigate.
"There are many examples of excellent reporting, but there is still room for improvement. Today's reforms will encourage companies to produce innovative and engaging reports, in line with current business best practice, and requiring them to disclose the number of senior women in the organisation will persuade companies to pursue greater diversity and develop the pipeline of talent, helping drive a long-term culture change at the heart of business."
Gender imbalances are put under the spotlight with the new legislations
Helen Wells, director of campaign group Opportunity Now, said the change showed how effective the Lord Davies review had been, adding: "Intent is being converted into action, without the need for quotas.
"These changes enable investors and shareholders to identify gender imbalances and better understand where the barriers to progression for women are in the organisation. We encourage shareholders and investors in these companies to deliver on this task."
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