Godzilla vs. King Ghidorah (Japanese: ゴジラvsキングギドラ, Hepburn: Gojira tai Kingu Gidora) is a 1991 Japanese kaiju film written and directed by Kazuki Ōmori and produced by Shōgo Tomiyama. Distributed by Toho and produced under their subsidiary Toho Pictures, it is the 18th film in the Godzilla franchise, and is the third film in the franchise's Heisei period. The film features the fictional monster characters Godzilla and King Ghidorah, and stars Kōsuke Toyohara, Anna Nakagawa, Megumi Odaka, Katsuhiko Sasaki, Akiji Kobayashi, Yoshio Tsuchiya, and Robert Scott Field. The plot revolves around time-travelers from the future who convince Japan to travel back in time to prevent Godzilla's mutation, only to reveal their true motives by unleashing King Ghidorah onto the nation.

The production crew of Godzilla vs. King Ghidorah remained largely unchanged from that of the previous film in the series, Godzilla vs. Biollante. Because the previous installment was a box office disappointment, due to a lack of child viewership and alleged competition with the Back to the Future franchise, the producers of Godzilla vs. King Ghidorah were compelled to create a film with more fantasy elements, along with time travel.

Godzilla vs. King Ghidorah was the first Godzilla film since 1975's Terror of Mechagodzilla to feature a newly orchestrated score by Akira Ifukube. The film was released theatrically in Japan on December 14, 1991, and was followed by Godzilla vs. Mothra released on December 12, 1992. It was released direct-to-video in North America in 1998 by Columbia TriStar Home Entertainment. Despite mixed reviews from critics, Godzilla vs. King Ghidorah was more financially successful at the box office than Godzilla vs. Biollante. The film attracted controversy outside Japan due to its perceived Japanese nationalist themes.