Gamera vs. Gyaos (大怪獣空中戦 ガメラ対ギャオス, Daikaijū kūchūsen: Gamera tai Gyaosu, lit. 'Giant Monster Midair Battle: Gamera vs. Gyaos') is a 1967 Japanese kaiju film directed by Noriaki Yuasa, with special effects by Yuasa. Produced by Daiei Film, it is the third entry in the Gamera franchise and stars Kojiro Hongo, Kichijiro Ueda, Tatsuemon Kanamura, Reiko Kasahara, and Naoyuki Abe, with Teruo Aragaki as Gamera. In the film, Gamera and authorities must deal with the sudden appearance of a carnivorous winged creature awakened by volcanic eruptions.

Plans for a third film were made immediately after the release of Gamera vs. Barugon, with the film financed by the UniJapan Film Association. Due to the underperformance of the previous film, Yuasa was brought back as the director and special effects director, who decided to aim the film towards children. Gyaos was created as a response to Toho's Frankenstein Conquers the World and The War of the Gargantuas, with Yuasa pitching to writer Niisan Takahashi his idea to turn Dracula into a kaiju.

Gamera vs. Gyaos was theatrically released in Japan on March 15, 1967, on a double bill with Chiisai Tôbôsha. That same year, it was released directly to television in the United States as Return of the Giant Monsters by American International Television.

The film was followed by Gamera vs. Viras, released on March 20, 1968.