The original run of The Twilight Zone produced 156 episodes. The American anthology series aired on CBS for five seasons, from October 2, 1959, through June 19, 1964.
Because the show was an anthology, each episode told a largely self-contained story, allowing its writers and directors to move between science fiction, horror, fantasy, satire, and psychological drama. Rod Serling served as creator, executive producer, principal writer, host, and narrator; he wrote or co-wrote 92 of the 156 episodes.
The series’ format changed during its run. Seasons 1–3 and 5 generally used half-hour episodes, while the fourth season expanded to an hour. That one-hour experiment contributed eight longer installments but did not alter the final episode total. Six second-season episodes were also recorded on videotape as a cost-saving measure, rather than filmed like most of the series.
The number 156 refers specifically to the 1959–1964 original series. It does not include the 1985, 2002, or 2019 revival series, nor the 1983 feature film. Those later productions are separate entries in the franchise.