Defense Secretary Ash Carter will order the military to open all combat jobs to women in 30 days, and the armed services will have to submit plans to make the historic change.
In a statement Thursday, he said the military will make "no exceptions" to allowing qualified women to serve in any position. Currently, women cannot hold about 10 percent of military jobs, including some infantry, reconnaissance and special operations posts, he said.
"We cannot afford to cut ourselves off from half the country's talent and skills," Carter said.
The decision rebuffs arguments from the Joint Chiefs of Staff chairman that the Marine Corps should be allowed to exclude women from certain front-line combat jobs, citing studies showing that mixed-gender units aren't as capable as all-male units.
"I believe that we could, in implementation, address the issues that were raised," Carter said.
A senior defense official told The Associated Press that all the services will have to begin putting plans in place by April 1.
Carter stressed that the Defense Department will not implement a quota for the number of female service members.
— The Associated Press contributed to this report.