Britain announced on Tuesday it would be putting girls and women at the heart of its work to end conflict in nine countries including Iraq, Nigeria and South Sudan.
"Empowering women and girls ... improves peace and stability, economic growth and poverty reduction," senior ministers said in a National Action Plan on Women, Peace and Security.
The ministers said women and girls were disproportionately affected by conflict, but were also part of the solution.
Evidence shows peace agreements are more likely to last when women are involved, according to the five-year plan launched late Tuesday.
"Without question women must have a seat at the table," Foreign Office minister Tariq Ahmad said in a statement.
"We know that when women and girls participate in political processes, conflict resolution and mediation their contribution helps to build a more sustainable peace."
Britain pledged to tackle obstacles to women's leadership and political participation, including entrenched patriarchal views, violence and intimidation.
The plan said women had a key role to play in developing strategies to prevent and counter extremism in their countries.
Britain will also push for peacekeeping missions to include more women, and support efforts to end sexual abuse by peacekeepers.
There were more than 140 allegations of sexual exploitation and abuse by U.N. staff and peacekeepers in 2016 and 2017, affecting more than 300 people.
The plan said evidence showed missions which included women were more effective and better able to engage with local people.
Ahmad also said championing girls' education was crucial for transforming the lives of those caught up in conflicts and promoting global stability.
"This year (we) will focus on ensuring that girls in the poorest countries in the world receive at least 12 years of quality education because this is the single most powerful spur to development and progress," he added.
The first action plan launched in 2014 focused on six countries: Afghanistan, Myanmar, the Democratic Republic of Congo, Libya, Somalia and Syria.
The new roadmap, launched by the foreign, defence and international development ministries, adds Iraq, Nigeria and South Sudan.
Although Iraq's constitution requires a quarter of lawmakers to be women, years of war and economic decline have undermined the status of women in most spheres of life, the plan said.
It also highlighted high levels of sexual violence amid South Sudan's civil war and in northeast Nigeria, where women face increased risks due to the conflict with Boko Haram militants.