Rebirth of Mothra, released in Japan as Mothra, is the first in a trilogy of kaiju eiga produced by Toho, in which Mothra's son saves the world from environment-threatening monsters. The so-called "Mothra Trilogy" marks a first for Toho: instead of later being incorporated into the Godzilla series, two daikaiju (King Ghidorah, who had debuted in the Godzilla film Ghidorah, the Three-Headed Monster) appear in spin-off films without Godzilla.

:This article is about the 1961 film. For the Godzilla Character, see Mothra.

Mothra is a 1961 daikaiju eiga (giant-monster movie) from Toho Studios, directed by genre regular Ishirō Honda with special effects by legend Eiji Tsuburaya. It is the kaiju eiga debut of screenwriter Shinichi Sekizawa, whose fantastic yet intelligent approach to the genre grew to prominence during the 1960s. The film stars Frankie Sakai, a popular comedian in Japan at the time, and Hiroshi Koizumi, in the first of many academic roles he would adopt in tokusatsu. Jerry Ito (transliterated as "Jelly Ito" in the credits of the U.S. release) delivers a fiendish performance, his only contribution to Toho's kaiju eiga genre. Ito also appeared in 1958's Japanese/US co-production "The Manster" (a.k.a. "The Split"), and in Toho's 1961 end-of-the-world sci-fi feature "Sekai Daisensou" ("The Last War"). The score by Yuji Koseki includes probably the most enduring song in kaiju eiga, "Mosura No Uta" ("Mothra's Song"), performed by The Peanuts.

The film did well at the box office but was panned by U.S. critics upon its stateside release as a typical B-grade monster-on-the-loose flick. Its basic plot was recycled in King Kong vs. Godzilla and Mothra vs. Godzilla (1962 and 1964, both also written by Sekizawa), and the daikaiju Mothra would become one of Toho's most popular, appearing in seven more Godzilla films and her own trilogy in the 1990s.

Shipwreck survivors are found on Beiru, an island previously used for atomic tests. Amazingly free of radiation effects, they believe they were protected by a special juice given to them by the natives. A joint expedition of Rolithican and Japanese scientists explores Beiru and discovers many curious things, including two women only a foot high. Unscrupulous expedition leader Clark Nelson abducts the women and puts them in a vaudeville show. But their sweet singing contains a telepathic cry for help to Mothra, the gigantic moth worshiped as a goddess by the island people. Mothra seeks the women in Tokyo, wreaking the usual havoc and special effects. Written by Molly Malloy

A logging and mining company working in Northern Japan disrupts a set of magical seals buried undergound, causing the release of Death Ghidora, an enormous, three-headed monster that had previously wiped out all life on Mars and caused the extinction of the dinosaurs on Earth. When Death Ghidora begins sucking the life out of the environment, the only thing that can save the planet from destruction is Mothra, the giant flying insect. Written by Jean-Marc Rocher