The painting featured in the movie at the beginning is titled "The Triumph of Death".

The title of the movie is inspired on the quote of First Thessalonians 5:2, which says "the day of the Lord so comes as a thief in the night".

The movie premiered at the 2017 Overlook Film Festival.

When shooting the scene where Paul interrogates Will, the boom operator had to sit in a tree for half the day to record the audio correctly.

There is a picture hanging in the hallway that is a tribute to Lil Wayne's Carter IV.

One of the pictures in the hallway is of Bill Withers, the singer famous for the hit song, "Lean on Me."

Joel Edgerton's character states that he was a teacher before the world started falling apart. Joel Edgerton's character was a teacher in the movie Warrior (2011).

Both Carmen Ejogo and Riley Keough also play in the anthology series The Girlfriend Experience, though their characters appear in separate seasons of the show.

Actor Kelvin Harrison Jr. (Travis) waxed his back before shooting his shower scenes to make his back look better.

For a majority of the movie every time Travis is dreaming the screen becomes cinema-scope style, transitioning out of cinema-scope style when he wakes up.

The cast and crew of the film signed a non-disclosure agreement that forbids them ever revealing what "comes" at night. However, fans and critics are in agreement that Travis's dreams are what "comes" at night.

Director Trey Edward Shults hinted that the two men attacking Paul & Will in the forest could be Father and Son; based on their similar appearance.

It's been speculated that Will could be a current/former alcoholic, judging by his demeanor when Paul brings out the Whiskey bottle.

At the end, it's heavily implied that Travis is dead, and that Paul & Sara are inflected. As Travis is absent from the table & Sara does not wear a mask when comforting Travis. Also Sara appears to have blackness in her right eye.