After the end of Buffy the Vampire Slayer, Gellar provided her voice for the character Gina Vendetti in The Simpsons episode "The Wandering Juvie", which aired in March 2004.
Her next film was Scooby-Doo 2: Monsters Unleashed (2004), reprising the role of Daphne.
While IGN felt that both Gellar and Prinze "exhibit marked improvements over their work in [2002's Scooby-Doo]", the film was a commercial success, grossing US$181.4 million around the globe.
In the horror remake The Grudge (also 2004), Gellar portrayed Karen Davis, an exchange student living and working in Tokyo who becomes exposed to a mysterious supernatural curse.
Critic Rob Blackwelder wrote that she "played her part well, and her fear and disorientation are terrifically enhanced by the decision to keep the [original] setting in this remake".
The film was a major box office hit, grossing more than US$110 million in the US, and US$187 million worldwide.
She received a MTV Movie Award nomination for Best Frightened Performance as well as a nomination for the Teen Choice Award for Choice Movie Actress – Thriller for her role.
Since 2005, she has voiced several characters in 13 episodes of the animated television series Robot Chicken, as of 2018.

Gellar starred opposite Dwayne Johnson, Seann William Scott, and Justin Timberlake in Richard Kelly's Southland Tales (2006), as an adult film star working on creating a reality television show.
Gellar had met with Kelly and was drawn to the original ideas for the movie, accepting the role before she even read the script.
The film found a limited audience in theaters, but J. Hoberman for Village Voice remarked that the director "contrives two memorable comic performances" by Gellar and Johnson.
In 2006, Gellar also briefly reprised her role of Karen in the critically panned sequel The Grudge 2, and starred in the psychological thriller The Return, as a businesswoman haunted by memories of her childhood and the mysterious death of a young woman.
The film was a critical and commercial failure, grossing only US$11 million.
The New York Times called it a "career stagnation".

In 2007, Gellar voiced Ella in the poorly received animated film Happily N'Ever After, and also April O'Neil in TMNT, which made US$95 million.
She starred in the romantic comedy Suburban Girl and the drama The Air I Breathe, both of which were screened at the 2007 Tribeca Film Festival.
In Suburban Girl, alongside Alec Baldwin, she took the role of a New York City editor and the love interest of a much older influential man (Baldwin).
The film was released for DVD in January 2008.
In the likewise little-seen film The Air I Breathe, Gellar appeared with Forest Whitaker, Brendan Fraser and Kevin Bacon, portraying an up-and-coming pop singer.
The New York Times called it a "gangster movie with delusions of grandeur", while DVD Talk noted that "her character here has the deepest emotional arc, and she hits all the right notes."

Possession, a psychological thriller Gellar filmed in 2006, saw her play a lawyer whose life is thrown into chaos after a car accident sends her husband (Michael Landes) and brother-in-law (Lee Pace) into comas.
Due to financial problems at Yari Film Group, the film went to DVD in March 2010.
In the film adaptation Veronika Decides to Die, Gellar starred as a young depressed woman who rediscovers the joy in life when she finds out that she only has days to live following a suicide attempt.
Like Possession, the film failed to find a proper release in North American theaters, and was released for VOD in 2015.
Frank Scheck of The Hollywood Reporter found the actress to be "reasonably compelling" in what he called a "ponderous and silly misfire".
After the end of Buffy the Vampire Slayer, Gellar provided her voice for the character Gina Vendetti in The Simpsons episode "The Wandering Juvie", which aired in March 2004. Her next film was Scooby-Doo 2: Monsters Unleashed (2004), reprising the role of Daphne. While IGN felt that both Gellar and Prinze "exhibit marked improvements over their work in [2002's Scooby-Doo]", the film was a commercial success, grossing US$181.4 million around the globe. In the horror remake The Grudge (also 2004), Gellar portrayed Karen Davis, an exchange student living and working in Tokyo who becomes exposed to a mysterious supernatural curse. Critic Rob Blackwelder wrote that she "played her part well, and her fear and disorientation are terrifically enhanced by the decision to keep the [original] setting in this remake". The film was a major box office hit, grossing more than US$110 million in the US, and US$187 million worldwide. She received a MTV Movie Award nomination for Best Frightened Performance as well as a nomination for the Teen Choice Award for Choice Movie Actress – Thriller for her role. Since 2005, she has voiced several characters in 13 episodes of the animated television series Robot Chicken, as of 2018.
Gellar starred opposite Dwayne Johnson, Seann William Scott, and Justin Timberlake in Richard Kelly's Southland Tales (2006), as an adult film star working on creating a reality television show. Gellar had met with Kelly and was drawn to the original ideas for the movie, accepting the role before she even read the script. The film found a limited audience in theaters, but J. Hoberman for Village Voice remarked that the director "contrives two memorable comic performances" by Gellar and Johnson. In 2006, Gellar also briefly reprised her role of Karen in the critically panned sequel The Grudge 2, and starred in the psychological thriller The Return, as a businesswoman haunted by memories of her childhood and the mysterious death of a young woman. The film was a critical and commercial failure, grossing only US$11 million. The New York Times called it a "career stagnation".
In 2007, Gellar voiced Ella in the poorly received animated film Happily N'Ever After, and also April O'Neil in TMNT, which made US$95 million. She starred in the romantic comedy Suburban Girl and the drama The Air I Breathe, both of which were screened at the 2007 Tribeca Film Festival. In Suburban Girl, alongside Alec Baldwin, she took the role of a New York City editor and the love interest of a much older influential man (Baldwin). The film was released for DVD in January 2008. In the likewise little-seen film The Air I Breathe, Gellar appeared with Forest Whitaker, Brendan Fraser and Kevin Bacon, portraying an up-and-coming pop singer. The New York Times called it a "gangster movie with delusions of grandeur", while DVD Talk noted that "her character here has the deepest emotional arc, and she hits all the right notes."
Possession, a psychological thriller Gellar filmed in 2006, saw her play a lawyer whose life is thrown into chaos after a car accident sends her husband (Michael Landes) and brother-in-law (Lee Pace) into comas. Due to financial problems at Yari Film Group, the film went to DVD in March 2010. In the film adaptation Veronika Decides to Die, Gellar starred as a young depressed woman who rediscovers the joy in life when she finds out that she only has days to live following a suicide attempt. Like Possession, the film failed to find a proper release in North American theaters, and was released for VOD in 2015. Frank Scheck of The Hollywood Reporter found the actress to be "reasonably compelling" in what he called a "ponderous and silly misfire".
Sarah Michelle Gellar