Godzilla (/ɡɒdˈzɪlə/ ɡod-ZIL-ə) is a giant monster, or kaiju, based on Toho Co., Ltd.'s character of the same name. The character first appeared in the 1998 film Godzilla, released by TriStar Pictures. Designed by Patrick Tatopoulos, he was modeled after iguanas with a slim theropod appearance rather than the thick, bipedal designs of Toho's Godzilla. He is the second incarnation of Godzilla to be reimagined by an American studio, after Hanna-Barbera's 1978 animated series Godzilla.

In 2004, a new iteration of TriStar's Godzilla was featured in Toho's 2004 film Godzilla: Final Wars as Zilla (ジラ, Jira). That version has since appeared in various media under the “Zilla” trademark, but with the variants from the 1998 film and Godzilla: The Series retaining the Godzilla copyright and trademark.

Initial reception towards the 1998 film and its version of Godzilla were generally negative, however, both would receive reappraise in later years. Reception for the animated sequel Godzilla: The Series was more favorable.

During the production of the 1998 film, special effects artist Patrick Tatopoulos was contacted by director Roland Emmerich and asked to create a new design for the Godzilla character. According to Tatopoulos, the only specific instructions Emmerich gave him was that he should be able to run incredibly fast. Emmerich intended to depict the character as an animal rather than a monster. Godzilla was originally conceived by special effects director Eiji Tsubaraya, special effects designers Akira Wantanabe and Teizo Toshimitsu and producer Tomoyuki Tanaka as a robust, erect-standing, plantigrade reptilian sea monster, played by an actor in a rubber-latex full-body suit. Based on the instructions Emmerich gave him, Tatopoulos reimagined him as a lean, digitigrade bipedal iguana who stood with his back and tail parallel to the ground, rendered via computer animation. The monster's distinctive facial features include a prominent lantern jaw, inspired by the fictional tiger Shere Khan from Disney's animated adaptation of The Jungle Book.

TriStar's Godzilla color scheme was designed to reflect and blend in with the urban environment. At one point, it was planned that motion capture would be used to create the movements of the computer-generated monster, though he ended up looking too much like a man in a suit. The Baby Godzilla scenes utilized a combination of CGI and purpose built costumes donned by actors. Kurt Carley portrayed the suitmation sequences for the adult Godzilla in the 1998 film while voice actor Frank Welker, foley artist Gary A. Hecker, and the film's sound designer Scott Martin Gershin provided additional vocals for both Godzilla and his offspring. Upon pending approval for the design, at the time, Shōgo Tomiyama commented on the new look, saying "It was so different we realized we couldn't make small adjustments. That left the major question of whether to approve it or not." Though TriStar's Godzilla was referred to by the film's characters as a "he", Patrick Tatopoulos stated on a DVD audio commentary that the effects crew sculpted female genitalia into the CG model of the creature.

In the 1998 film and animated series, TriStar's Godzilla is portrayed as a territorial, piscivorous, 180 feet (54.86 m) tall mutated lizard. Atypical of Toho's giant monster characters, TriStar's Godzilla is not immune to conventional weaponry, and instead relies on his cunning and athleticism to outflank his enemies. He can travel long distances over land and sea, burrow underground, and, reproducing asexually via parthenogenesis, able to lay over 200 eggs, unlike his offspring in the animated series, Zilla Jr., who was unable to reproduce. He possesses an ignitable radioactive breath weapon called "Power Breath", although his offspring could breathe a green atomic Power Breath in the animated series (where the parent Godzilla is resurrected as a cyborg called Cyber-Godzilla who possessed a blue version), in which he was pitted against a rogues gallery of original monsters, after the producers were unable to secure the rights to adapt Toho's classic monsters. He was also featured in advertisements alongside the Taco Bell chihuahua.

During production of Godzilla: Final Wars, director Ryuhei Kitamura asked producer Shōgo Tomiyama whether or not they were allowed to include TriStar's Godzilla in the film. Tomiyama checked Toho's contract with Sony and saw they were allowed to use him, stating, "since this was the 50th anniversary film, I thought 'Why not include the American Godzilla?'" This incarnation of TriStar's Godzilla was named "Zilla". This decision was made because they also felt that Emmerich's film had taken the "God" out of "Godzilla" by portraying the character as a mere animal, however, Kitamura admitted to "liking" the 1998 film and Emmerich's works. The name "Zilla" was chosen for the character by Tomiyama as a satirical take on counterfeit Godzilla products that use "Zilla" as a suffix. In the film, Zilla is one of many monsters controlled by the Xilliens in their invasion against Earth who engages Godzilla in a battle in Sydney before he is quickly defeated by him. A 3D scan of the Trendmasters "Ultimate Godzilla" toy was used as reference for Zilla.

Zilla would fight Godzilla again in a slightly longer battle, and even team up with Godzilla to fight other monsters, in the comic series by IDW Publishing titled Godzilla: Rulers of Earth running between 2013 and 2015.