The film was shot in 36 days.

In an interview with Chris Stuckmann, Colin Trevorrow stated the screenplay was twenty years old.

This was the second collaboration between Jacob Tremblay and Naomi Watts. Their first collaboration was in Shut In (2016).

Naomi Watts and Jaeden Lieberher previously starred together in St. Vincent (2014).

Big screen debut of Maddie Ziegler.

Director Colin Trevorrow said he first read a version of the screenplay, that was "much more of a black comedy", but he "wasn't really interested" in making such a movie, therefore it was changed.

Jaeden Lieberher (Henry) and Bobby Moynihan (John) have both appeared in a movie or TV show with Jack Dylan Grazer. Lieberher starred alongside Grazer in the 2017 remake of Stephen King's It. Jack Dylan Grazer portrays Moynihan's 14 year old self in Me, Myself and I.