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.

While critics have remarked on the film's references to early-period Steven Spielberg, director Colin Trevorrow does not consider himself a personal fan of Spielberg's work.

Dean Norris's police chief character was given the surname "Sickleman" because, as director Colin Trevorrow put it, he was "quite the 'sick' 'lil' 'man'!"