This article or section reveals details from the fourth season. Read at your own discretion...
Cast and characters
- Winona Ryder as Joyce Byers
- David Harbour as Jim Hopper
- Finn Wolfhard as Mike Wheeler
- Millie Bobby Brown as Eleven
- Gaten Matarazzo as Dustin Henderson
- Caleb McLaughlin as Lucas Sinclair
- Noah Schnapp as Will Byers
- Sadie Sink as Max Mayfield
- Natalia Dyer as Nancy Wheeler
- Charlie Heaton as Jonathan Byers
- Joe Keery as Steve Harrington
- Maya Hawke as Robin Buckley
- Priah Ferguson as Erica Sinclair
- Cara Buono as Karen Wheeler
- Brett Gelman as Murray Bauman
- Jamie Campbell Bower as Peter Ballard
- Eduardo Franco as Argyle
- Joseph Quinn as Eddie Munson
- Tom Wlaschiha as Dmitri
- Nikola Đjuričko as Yuri
- Mason Dye as Jason Carver
- Sherman Augustus as Lt. Colonel Sullivan
- Robert Englund as Victor Creel
- Joel Stoffer
- Levon Thurman-Hawke
- Mica Shemper
- Matthew Modine as Martin Brenner
|26||"The Hellfire Club"||The Duffer Brothers||The Duffer Brothers|
Following the release of Season 3, the Duffer Brothers stated that should Stranger Things get a renewal for the fourth season (renewal was confirmed two months later), the season would be very different and would explore newer locations outside Hawkins in order to "open up plot-lines". They also confirmed the season would address the mid-credits scene of the finale of the third season.
In early February 2020, it was reported that the season's length had been extended to nine episodes. 
In mid-February, in addition to releasing a teaser trailer, the Duffers revealed the return of Jim Hopper who's now imprisoned in Kamchatka, likely confirming that he was the American prisoner discussed in the end credit scene of season 3. They added that the season would be the "most frightening yet" with "a new horror" emerging that would connect everything.
In an appearance at Liverpool Comic Con, actor David Harbour teased that Hopper's backstory will be explored in the upcoming season. Actor Joe Keery stated that the fourth season would be "a lot scarier" than previous seasons. Actress Sadie Sink also mentioned that the teens will be entering high school during the season. In mid-August, the Duffer brothers confirmed that all of the scripts have already been completed and were just being adjusted. 
On July 1, 2020, it was announced that Joel Stoffer had been cast in an undisclosed role. 
On November 20, 2020, it was officially announced that Robert Englund, Eduardo Franco, Jamie Campbell Bower, Sherman Augustus, Mason Dye, Tom Wlaschiha, Nikola Đjuričko, and Joseph Quinn had joined the cast for the fourth season, with Eduardo Franco, Jamie Campbell Bower, and Joseph Quinn updated to series regulars. 
According to a report made by TV Line, Season 4 was slated to begin filming in January 2020.
Following the release of a teaser on February 14, the Duffer brothers confirmed that filming for the fourth season had already begun.
According to a listing in Production Weekly, the season was being filmed under the working title "Tareco". Shooting took place in Vilnius, Lithuania and later moved back to Atlanta, before filming came to a halt due to COVID-19 outbreak. According to stunt co-ordinator Hiro Koda, two episodes of the season were filmed before production was halted. 
On October 1, 2020, it was officially confirmed that filming for the fourth season has resumed again. On the occasion of Stranger Things Day, photos of Gaten Matarazzo, Joe Keery, Sadie Sink and Caleb McLaughlin during filming takes were released on November 6. 
On January 27, 2021, Jamie Campbell Bower and Matthew Modine were spotted filming scenes in Atlanta, Georgia.
Effect of COVID-19 outbreak
Following the outbreak of the pandemic COVID-19, Netflix decided to halt production on all its films and TV series, including the fourth season of Stranger Things on March 13, 2020, for at least two weeks. However, filming for the season resumed at the end of September 2020, 6 months since production came to a halt.
- This is the second season to have nine episodes since Season 2.
- As part of a joke, the Stranger Things Writers Twitter account revealed the episode names of Chapter 2, 3 and 4, before subsequently confirming the names to be misleading. The episode names were "Tick Tok Mr Clock", "You Snooze You Lose" and "Wakey Wakey Eggs and Bakey" respectively. 
The first teaser trailer was released on September 30, 2019, alongside the season's official announcement.
A clip from the fourth season was released on February 14, 2020, which confirmed the fate of Hopper. Another teaser trailer showing the Season 4 table read was released on March 3, 2020.
- Twitter post from the official writers' account
- "Stranger Things 4 officially announced with new teaser" Entertainment Weekly. September 30, 2019
- "Agents of SHIELD's Joel Stoffer to Appear on Stranger Things (Exclusive)"Comicbook. July 1, 2020.
- Chapter One title revealed via the show's writers
- ‘Stranger Things 4’ First Look Trailer Confirms David Harbour’s Hopper Is Alive and Returning"Indiewire. February 14, 2020.
- David Harbour: Hopper’s ‘Stranger Things’ Return Includes ‘Huge’ Backstory RevealIndiewire.. May 5, 2020.
- 'Stranger Things' Creators on Their Departure From Halloween Spookiness and Season 4 PlansThe Hollywood Reporter. August 18, 2020.
- "‘Stranger Things’ Ups Priah Ferguson to Series Regular for Season 4 (EXCLUSIVE)" Variety. February 21, 2020.
- ‘Stranger Things’ Season 4: ‘Fleabag’s Brett Gelman Upped To Series Regular" Deadline. March 3, 2020.
- Official Twitter thread revealing new season 4 charaters.Novemeber 20, 2020
- "Stranger Things Season 4 Working Title Revealed"Comicbook. December 9, 2019.
- "Stranger Things: Stunt Coordinator Hiro Koda Teases “Darker” Season 4, Explains How Social Distancing Will Affect Stunts "Comicbook. May 23, 2020.
- "Official Twitter Post" October 1, 2020.
- "Official Twitter Post" November 6, 2020
- ‘Stranger Things,’ Producers on Shutting Down: ‘It’s Bittersweet’"Variety. March 18, 2020.
- Stranger Things Writers' Twitter Post