Army, Navy and Air Force leaders, along with officials who manage joint assignments that cut across the services, have been told to finish the reductions by Jan. 1, 2027.
The jobs are called billets, which are an authorized slot on an organizational chart, and the kind of job that is supposed to be filled by a one-star officer or higher.
Generals serve in the Army, Air Force, Marine Corps and Space Force, while admirals serve in the Navy. Together they are often called general and flag officers.
Cutting 20 percent does not, by itself, require the Pentagon to fire one in five officers who currently wear those ranks. Some of the jobs will be downgraded, and in those cases, a colonel or a Navy captain could fill a post that used to require a general or admiral.
The new target doubles the 10 percent overall reduction Hegseth ordered last year.
That earlier directive also called for a 20 percent cut in active-duty four-star positions and a 20 percent cut among National Guard general officers.