[4] Lego Stranger Things was based on the Stranger Things 2016 Netflix sci-fi horror series, which focuses on the investigation into the disappearance of a young boy (Will Byers) amid supernatural events occurring around the town, including the appearance of a girl with psychokinetic abilities (Eleven).

Lego Stranger Things aimed to recreate the main characters in Lego form, including Barbara "Barb" Holland, Eleven / Jane Hopper, Mike Wheeler, Lucas Sinclair, Dustin Henderson, Will Byers, Joyce Byers, Chief Jim Hopper, and the Demogorgon.

[11] As part of the marketing campaign, The Lego Group released The Upside Down (set number: 75810) based on a version of the Byers' home.

It also included Chief Jim Hopper's police truck and a variety of accessories.

[19][20][21][4] In July 2019, San Diego Comic-Con announced that an exclusive Barb minifigure would be given away to the winners.

[27][4] The product line was accompanied by a series of animated short films released on YouTube.