The shift benefits Kimmel since his show will start at the same time as other late-night shows. It will give Kimmel a chance to build his audience since the first few minutes is important in determining if a viewer will continue to watch.
The move will cut "Nightline," which had been airing from 11:35 p.m. to 12:05 a.m. EST, to 25 minutes instead of a half-hour.
The news program, however, will gain a series of 13 prime-time episodes, said ABC. The network also intends to trim the commercial time within "Nightline" to largely preserve the program's content, a spokeswoman said.
The Associated Press contributed to this report.