For his ceremony scene, actor Jung-min Hwang filmed for 15 minutes without break. It was one long-take scene.

According to director Na Hong-jin, this movie was made on the basis of folk religions in Korea and Nepal and on Catholic faiths.

The Wailing is Jun Kunimura's first Korean film in his 35-year acting career.

Exorcism scenes by the Japanese Man stem from Shamanism in Nepal.

No higher animals (the worm in the beginning is per definition not a higher animal) were harmed for the making of this movie. The animal scenes were done after consulting with animal trainers and under observation. The film also had a staff for VFX.

The movie contains many themes but is mainly based on folk religions in Korea.

Ari Aster's favourite horror movie of the last 10 years (as of 2019)

The stone throwing by white women scene alludes to An allusion to an utterance of Jesus' in John 8:7, viz. "He that is without sin among you, let him first cast a stone at her."

The prayer that Yang Yi-sam, Do-yoon Kim says when he's entering the cave is the Prayer to St.Michael.

Jun Kunimura's camera at the end of the film is a Minolta Hi-Matic S, which was released in 1978.

Hong-jin Na's 3rd feature film.

The white women collects upper body belongings from villagers to protect them and Japanese man collects lower belongings like shoes to curse on them.

Originally, this film had chasing scenes between The Woman of No Name (Woo-hee Chun) and The Stranger (Jun Kunimura), but director Na Hong-jin deleted the scenes. He thought they might cheapen the mystique of Woo-hee Chun's character.

Hwan-hee Kim who played Hyo-jin (Jong-goo's daughter) practiced modern dance for 6 months to perform scenes of her being possessed by the devil.

Foreshadow hint: The shaman wears same diaper as Japanese man.

This film mentioned directly and indirectly all the biblical sins.