September 2026 heralds a diverse slate of streaming content, ranging from action-packed adventures and returning comedies to intriguing sci-fi finales and biographical dramas. Prime Video expands its popular Reacher universe with a new spin-off, while Apple TV+ continues its streak with new seasons of Slow Horses and a unique series starring Woody Harrelson and Matthew McConaughey. The month also promises new installments of South Park and The Paper, alongside a fresh take on the Lizzie Borden story and a potential game-changer for Star Trek: Strange New Worlds.
New Series and Seasons
Apple TV+ kicks off the month with Mayday on September 4, a throwback action-adventure starring Ryan Reynolds and Kenneth Branagh. Directed and written by the duo behind Game Night and Dungeons & Dragons: Honor Among Thieves, Jonathan Goldstein and John Francis Daley, the film centers on an American pilot stranded in Soviet Russia who must team up with a defecting ex-KGB agent. Later in the month, on September 23, the streamer will debut Brothers, a metafictional series starring Woody Harrelson and Matthew McConaughey as semi-fictionalized versions of themselves exploring a potential shared family history, drawing parallels to Yellowstone.
Peacock's comedy The Paper returns for its second season on September 9. After a first season that found its footing in its final episodes, the series, an apparent spin-off of The Office, will aim to build on its ensemble cast and character dynamics. Gary Oldman returns as the disgraced spy chief in Slow Horses Season 6 on Apple TV+ on September 16. The new season will be helmed by new showrunner Gaby Chiappe, who takes over from creator Will Smith, and will draw from Mick Herron's novels Joe Country and Slough House.
Prime Video's Reacher universe expands on September 16 with the debut of Neagley. Starring Maria Sten as the titular character, the spin-off will follow her as she investigates a personal mystery, premiering all its episodes on the same day as the Reacher Season 4 finale. Also on September 16, Comedy Central's long-running animated series South Park returns for its 29th season, expected to continue its satirical commentary on current events. On September 17, Netflix's anthology series Monster shifts its focus to female killers with Monster: The Lizzie Borden Story. Ella Beatty stars as the infamous axe murderer, alongside a cast that includes Charlie Hunnam, Sarah Paulson, and Billie Lourd.
Notable Season Finales and Revivals
Star Trek: Strange New Worlds concludes its season with an episode titled "Tomorrow's Enterprise" on September 24. The title alone has generated significant speculation, potentially hinting at time travel scenarios or connections to the Enterprise-G seen at the end of Picard Season 3, especially given the franchise's 60th anniversary.
A different kind of return comes on September 24 with the revival of the sitcom A Different World. This legacy sequel is set at Hillman College and follows the daughter of original characters Whitley and Dwayne as she navigates her freshman year, balancing academics, social life, and likely contemporary issues. While it retains the original cast members, the new series will adopt a single-camera format, diverging from the original's three-camera setup.
Finally, Netflix will release Unabomber on September 25, a dramatization of Ted Kaczynski's life. The film stars Jacob Tremblay as Kaczynski across two timelines: during the manhunt and his time at Harvard. The cast also includes Russell Crowe and Shailene Woodley, with direction from Janus Metz Pedersen, who previously helmed episodes of Andor.