In 1997, Ricci began to appear in more adult roles, beginning with her role as the troubled, sexually curious Wendy Hood in Ang Lee's critically acclaimed The Ice Storm. Ricci subsequently appeared in films like the independent hit Buffalo '66 (in which she played Vincent Gallo's unwitting abductee-turned-girlfriend), John Waters' Pecker, and Don Roos' The Opposite of Sex (as the acid-tongued, manipulative Dede). For her performance as Dede, Ricci won acclaim and was nominated for a Golden Globe and attained the unofficial title of the Sundance Film Festival's 1998 "It" Girl. Although she missed out on an Academy Award nomination, Entertainment Weekly honored her well-received performance as one of the "Worst Oscar Snubs Ever". Later films included Sleepy Hollow (alongside Johnny Depp), and Prozac Nation (which featured her first on-screen nude scene). She starred opposite Charlize Theron in the film Monster. During Theron's acceptance speech at the Golden Globes, she acknowledged Ricci, calling her the "unsung hero" of the film. Ricci had to turn down the role of Ronna in Go because of scheduling conflicts; the role eventually went to Sarah Polley. Ricci was turned down four times for the role of Dolores Haze in Lolita, and the role eventually went to Dominique Swain. Ricci was originally slated to play the lead in Ghost World (2001), but by the time it was filmed she was too old for the part and had moved on to other projects. Thora Birch (Ricci's co-star in Now And Then) took over the role. Ricci also turned down a role in Loser. Ricci made a cameo appearance on Beck's successful Guero, providing the voice on "Hell Yes".

In February 2006, Ricci made a guest appearance as a paramedic in the ABC drama Grey's Anatomy, for which she was nominated for an Emmy award. She was a guest star for seven episodes in the last season of Ally McBeal in 2002 as Debbie 'Liza' Bump, a lawyer who worked at Cage & Fish and married Richard Fish in the last episode. It was initially hoped that Ricci and several other noted guest star appearances would boost Ally McBeal's then declining ratings. On December 4, 1999, she appeared as the guest host on Saturday Night Live. She performed parodies of Britney Spears and the Olsen Twins. During one of her skits, she accidentally punched actress Ana Gasteyer in the face. The skit was a parody of the Sally Jessy Raphael show, in which she played a 13-year-old runaway who sleeps with dogs, and required her to fake-punch Gasteyer, but accidentally ended up really hitting Gasteyer in the eye. Although Ricci initially reacted by putting her hands over her mouth in surprise, she quickly fell back into character.

In 2006, Ricci stated that she feels that at 5 ft 1 in (155 cm) she is "too short" to ever be an A-list actress, saying she tends "to look really small on camera". She has also said that she believes that she does not have much control over her career, specifying that she still has to audition for film parts. Her 2007 film, Black Snake Moan received mixed reviews, with rottentomatoes.com tallying an overall score of 66 percent. On the television program Ebert & Roeper, filmmaker Kevin Smith, filling in for Roger Ebert, described the film as the best of the year thus far and called it Ricci's best performance. Richard Roeper also gave the film a "thumb up" rating. The film earned $4 million, putting it in eighth place for the highest earnings in its opening weekend. For her role in Black Snake Moan, Ricci was required to lose several pounds and wore a forty-pound (18 kg) chain during filming. Apart from having to lose weight, Ricci ate only food items without any nutritional value to achieve her unhealthy appearance. Ricci has starred in Penelope, alongside Reese Witherspoon, a modern day fairytale, and in 2008, she played the female lead in The Wachowski Brothers' feature film adaptation of Speed Racer. In February, along with Samuel L. Jackson, she presented an Award at the 2007 Grammys. Ricci is currently filming the psychological thriller After.Life in New York with Liam Neeson and Justin Long, and has signed on for three episodes of TNT's crime drama Saving Grace, which recently began its second season. Ricci will play a young detective who temporarily partners with Grace, played by Holly Hunter.

• Long Time Gone (2009) (pre-production)
• Alpha and Omega (2010) (post-production) .... Lilly
• The Hero of Color City (2010) (post-production) (voice) .... Yellow
• After.Life (2009) (post-production) .... Anna Taylor
• All's Faire in Love (2009) (post-production) .... Kate
  
• The Legend of Spyro: Dawn of the Dragon (2008) (VG) (voice) .... Cynder
• New York, I Love You (2008) .... Camille
  ... aka New York, je t'aime (France: literal title)
• Speed Racer (2008) .... Trixie
  ... aka Speed Racer (Germany)
  ... aka Speed Racer: The IMAX Experience (USA: IMAX version)
• Home of the Brave (2006) .... Sarah Schivino
• Black Snake Moan (2006) .... Rae
• Penelope (2006) .... Penelope Wilhern
• "Grey's Anatomy" .... Hannah Davies (2 episodes, 2006)
       - As We Know It (2006) TV episode .... Hannah Davies
       - It's the End of the World (2006) TV episode .... Hannah Davies
• Cursed (2005) .... Ellie Hudson
  ... aka Verflucht (Germany)
  ... aka Wes Craven's Cursed (USA: complete title)
• "Joey" .... Mary Teresa (1 episode, 2005)
       - Joey and the Fancy Sister (2005) TV episode .... Mary Teresa
• Monster (2003) .... Selby
• I Love Your Work (2003) .... Shana
• Anything Else (2003) .... Amanda Chase
  ... aka Anything else, la vie et tout le reste (France)
  ... aka Vie et tout le reste, La (France)
• "Ally McBeal" .... Liza Bump (7 episodes, 2002)
       - Bygones (2002) TV episode .... Liza Bump
       - All of Me (2002) TV episode .... Liza Bump
       - What I'll Never Do for Love Again (2002) TV episode .... Liza Bump
       - Another One Bites the Dust (2002) TV episode .... Liza Bump
       - Tom Dooley (2002) TV episode .... Liza Bump
        (2 more)
• "Malcolm in the Middle" .... Kelly (1 episode, 2002)
       - Company Picnic: Part 1 (2002) TV episode .... Kelly