* TheDanza: Yoko Maki as Yoko.
* ExecutiveMeddling: Kayako did not have much of a backstory in the original film series, and Takashi Shimizu wanted to keep it that way. However, he was told to give her a backstory for ''The Grudge 2'', which he reluctantly went ahead with . In an interview, Shimizu also stated that executives kept insisting that Kayako should have "a twin", which baffled him. In ''The Grudge 3'', Kayako is revealed to have a sister (though not a twin sister), which has to make one wonder if that was a case of executive meddling, too.
* HeyItsThatGuy: Creator/SarahMichelleGellar as Karen is the most obvious example.
** Aubrey is played by [[JoanOfArcadia Amber Tamblyn]].
** Ryo Ishibashi, who plays Detective Nakagawa, is well-known for his roles in ''{{Audition}}'' and ''SuicideClub''.
** Alex is played by Ted "[[XenaWarriorPrincess Joxer the Mighty]]" Raimi, Sam Raimi's brother.
** Isao Yatsu, who plays [[{{Expy}} the senile old man on the bus]], also appeared in the third ''Ju-on'' movie playing a similar role, and previously appeared as the apartment manager Kamiya in ''Film/DarkWater''. He also had a part in ''Film/{{Infection}}''.
** Yoko Maki, [[TheDanza who plays Yoko]], has appeared in ''LightNovel/KamikazeGirls'', ''Film/{{Infection}}'' and ''Literature/BattleRoyale II: Requiem''.
** This also isn't the first time that Creator/SarahMichelleGellar and Jason Behr (Doug) have appeared on-screen together - Behr played Billy Fordham in the ''Series/BuffyTheVampireSlayer'' Season 2 episode "Lie To Me". Additionally, Clea [=DuVall=] (Jennifer) appeared in a Season 1 episode, "Out of Mind, Out of Sight".
** Additionally, Clea [=DuVall=] and [=KaDee=] Strickland (Susan) have previously appeared in another movie together, ''GirlInterrupted''.