The 1999–2000 network television schedule for the six major English language commercial broadcast networks in the United States covers primetime hours from September 1999 through August 2000. The schedule is followed by a list per network of returning series, new series, and series cancelled after the 1998–99 season.

PBS is not included; member stations have local flexibility over most of their schedules and broadcast times for network shows may vary. Also not included are stations affiliated with Pax TV; although Pax carried a limited schedule of first-run programs, its schedule otherwise was composed mainly of syndicated reruns.

New series highlighted in bold.

All times are U.S. Eastern and Pacific Time (except for some live sports or events). Subtract for one hour for Central, Mountain, Alaska and Hawaii-Aleutian times.

Each of the 30 highest-rated shows is listed with its rank and rating as determined by Nielsen Media Research.^[1]

Note: On Fox, Ally aired as re-edited half-hour repeats of the original hour-long Ally McBeal series. On CBS, Falcone premieres at 9:00 p.m. on April 4, 2000. On UPN, Secret Agent Man was supposed to premiere at 9:00pm, but however due to the show not getting the "buzz" before the fall premiere, The Strip was premiered instead, and the show aired later on in a different night.

Note: On ABC, Clerks premiered at 9:30 p.m. on May 31, 2000.

Note: On NBC, the sitcom Daddio premiered on March 23, 2000, at 8:30. On Fox, Family Guy only had two airings and one special Sunday airing, and then on March 7, 2000, the show was moved to Tuesdays. On The WB, Popular premiered Wednesday, September 29, 1999, at 9:00 pm. On Fox, Manchester Prep was supposed to air at 8–9, but it was cancelled at the last minute. On ABC, Then Came You was scheduled to air at 8:30 PM EST, but due to the show not getting the "buzz" before the fall premiere, Whose Line Is It Anyway? was aired at the last minute, and the show aired later on in a different night.