After the release of Eclipse, the first three "Twilight" books spent a combined 143 weeks on The New York Times Best Seller list. The fourth installment of the Twilight series, Breaking Dawn, was released with an initial print run of 3.7 million copies. Over 1.3 million copies were sold on the first day. The novel won Meyer a British Book Award for Children's Book of the Year, despite competition from J. K. Rowling's The Tales of Beedle the Bard. In 2009, Meyer faced plagiarism accusations for Breaking Dawn. Author of The Nocturne, Jordan Scott, claimed the circumstances around Bella's supernatural pregnancy and subsequent transformation into a vampire were similar to the storyline of her novel and indicated that Meyer plagiarized the plot of The Nocturne. Meyer dismissed the accusation, claiming she had not heard of the writer nor the novel. Scott failed to produce a copy of the novel to support her accusation; The Nocturne is not available on Amazon and is listed as "temporarily sold out" on her website.
Following the success of Twilight, Summit greenlit a film adaptation of the sequel, The Twilight Saga: New Moon. Each novel adaptation was headed by a different director, chosen by Summit in order to provide each film a different atmosphere already existent in the novels. Chris Weitz directed New Moon, which was released on November 20, 2009. On opening night, New Moon broke the record for the highest single-day domestic gross on opening day which had previously been set by Harry Potter and the Half-Blood Prince. Despite its commercial success, the film received poor reviews; Roger Ebert criticized the slow pace of the film and Tim Robey of The Telegraph similarly said, "the movie gives us all the requiste looks of tortured longing, and not a lot else". Directed by David Slade, The Twilight Saga: Eclipse, an adaptation of the third book in the series, was released on June 30, 2010. An article from The Guardian reported that it was the best film of the series according to critical consensus for being more "cinematic" and striking a better balance between romance and the supernatural. However, an article from The Telegraph, rebutted The Guardian's claim, arguing that Twilight remined the best film in the series due to the "entirely straight-faced contrast between the forces of eternal darkness and the rigors of high school". Having already obtained the rights to Breaking Dawn, Summit approved a two-part adaptation.
In 2009, Stephenie Meyer was included in the Forbes Celebrity 100 list of the world's most powerful celebrities, entering at No. 26. Her annual earnings exceeded $50 million. The same year, Meyer was ranked No. 5 on Forbes' list of "Hollywood's Top-Earning Women", the only author on the list, and it was noted that the "Twilight series of young-adult vampire books have taken the publishing and film worlds by storm." In 2010, Forbes ranked her as the No. 59 most powerful celebrity with annual earnings of $40 million.
In August 2009, USA Today revealed that Meyer broke J. K. Rowling's record on their bestseller list; the four Twilight books had spent 52 straight weeks in the top 10. In all, the books have spent more than 235 weeks on The New York Times Best Seller list. Upon the completion of the fourth entry in the series, Meyer indicated that Breaking Dawn would be the final novel to be told from Bella Swan's perspective. In 2015, she published a new book in honor of the 10th anniversary of the best-selling franchise, titled Life and Death: Twilight Reimagined, with the genders of the original protagonists switched.
In April 2009, Meyer took part in Project Book Babe, a benefit designed to help pay her friend Faith Hochhalter's medical bills after Hochhalter was diagnosed with breast cancer. Meyer donated many advance reader copies and original manuscripts for auction.
Inspired by Meyer's Twilight series, evolved a genre of geek rock called "Twi-rock", similar in purpose to wizard rock inspired by J.K. Rowling's Harry Potter series. Examples of these Twilight-themed bands include the Bella Cullen Project, Twilight Music Girls, Be Safe Bella, Bella Rocks, and the Mitch Hansen Band. The Mitch Hansen Band wrote the song "By You" in hopes that it would be included on the New Moon film soundtrack. An unofficial Twilight themed fan convention called TwiCon was organized in Dallas, Texas in summer 2009 which included "Twi-rock" band performances, a Volturi Ball, panels, workshops, and vendors.