Returning as series regulars are Winona Ryder, David Harbour, Finn Wolfhard, Millie Bobby Brown, Gaten Matarazzo, Caleb McLaughlin, Noah Schnapp, Sadie Sink, Natalia Dyer, Charlie Heaton, Joe Keery, Maya Hawke, Priah Ferguson, Brett Gelman, Cara Buono, and Jamie Campbell Bower.
Amybeth McNulty was promoted to series regular after appearing as a guest in the previous season, while Linda Hamilton joined the main cast in an undisclosed role.
However, due to disruptions caused by the COVID-19 pandemic, the Duffers were able to completely outline the fifth season before the fourth had even begun shooting, which was a departure from their usual development cadence.
[20] On September 27, the day that the strike ended, the Stranger Things Writers account posted an image stating "We're back",[21] officially confirming that writing had resumed.
Netflix reportedly would prioritize writing this script because Stranger Things was profitable and because the actors, though still young, could not continue to portray teenagers forever.
[23] The fifth season features the return of Winona Ryder, David Harbour, Finn Wolfhard, Millie Bobby Brown, Gaten Matarazzo, Caleb McLaughlin, Noah Schnapp, Sadie Sink, Natalia Dyer, Charlie Heaton, Joe Keery, Maya Hawke, Priah Ferguson, Brett Gelman, Cara Buono, and Jamie Campbell Bower.
[28][29] Amidst filming in mid-October 2024, a casting call was announced by Knight Edge Media for Jim Hopper's late daughter Sara, who was previously portrayed by Elle Graham in the first season, with indications she would similarly feature in flashback sequences with a requirement of the chosen actress to resemble Graham back then.
[39][40] In January 2025, the Duffer brothers announced that post-production for the season was underway and that work on the visual effects was "ahead of schedule".