US Defense Secretary Ash Carter has announced that all combat roles in the US military will be opened to women.
“America’s force of the future,” Mr Carter said, must be able to benefit from the “best people” the US had to offer.
The move will lead to some 220,000 openings to women, he said.
Mr Carter is to give the armed services until 1 January next year to submit plans to make the change, officials said.
A ban on women serving in combat roles was lifted in 2013 but the military was given until 2016 to argue for specific posts they think should remain closed.
The Marine Corps had argued that women should be excluded from certain roles, citing studies that mixed-gender units were not as capable as all-male ones.