In the real world
- 11 January: Shin Ultraman begins a two-night engagement in U.S. theaters via Fathom Events.
- Mid-January: SRS Cinema releases 1967's Space Monster Wangmagwi to Blu-ray and VHS, the film's first home video releases anywhere in the world.
- 8 February: The IDW Publishing miniseries Godzilla: Monsters & Protectors - All Hail the King! concludes with its fifth issue.
- 7 March: The GODZILLA OFFICIAL by TOHO YouTube channel begins uploading episodes of Godzilla Island with English subtitles, the series' first official translation.
- 22 March: Godzilla: Tokyo SOS screens in the U.S. for one night only via Fathom Events.
- 1 April: Chibi Godzilla Raids Again premieres on TV Tokyo.
- 4 April: Discord user @EliteFreakozoid discovers an active web address for Slusho.com which had originally redirected to Slusho.jp.
- 5 April: Slusho.com becomes active.
- 12 April: Toho releases Shin Ultraman to 4K Ultra HD, Blu-ray, and DVD in Japan, with Shin Ultra Fight included as a bonus feature on the 4K Ultra HD combo pack and the three-disc Blu-ray.
- 19 April: The title for the 5th Monsterverse film is confirmed via teaser as Godzilla x Kong: The New Empire
- 1 June: Evil Genius Games publishes the physical edition of the Kong: Skull Island Cinematic Adventure.
- 2 June: Yukiko Takayama passes away at age 83.
- 13 June: Cleopatra Entertainment releases Shin Ultraman to Blu-ray and DVD in the U.S.
- 22 June: The anime Skull Island is released by Netflix.
- 17 August: A graphic novel adaptation of the film Notzilla is announced, alongside a Kickstarter campaign.
- 24 August: Warner Bros. delays Godzilla x Kong: The New Empire to April 12, 2024.
- 1 September: The GAMERA -Rebirth- incarnations of Gamera and Gyaos are announced to be added in the Godzilla Battle Line game.
- 5 September: Titan Manga publish the first volume of the manga adaptation of The Great Yokai War: Guardians.
- 7 September: GAMERA -Rebirth- is released on Netflix.
- 29 September: A banner for Godzilla x Kong: The New Empire is spotted at Toy Fair.
- 3 October: University of Minnesota Press publishes an English translation of Shigeru Kayama's novelizations of Godzilla and Godzilla Raids Again.
- 17 October: Skull Island: Rise of Kong is released.
- 21 October: Hoshi 35 is released in Japan.
- 3 November: Godzilla Minus One is released in Japan. The short films Godzilla vs. Megalon and Fest Godzilla 4: Operation Jet Jaguar are shown at Godzilla Fest.
- 9 November: A star system discovered by NASA is named after Mothra.
- 17 November: The first two episodes of Monarch: Legacy of Monsters premiere on Apple TV+.
- 30 November: Gamera 2: Attack of Legion will begin a one-week 4K re-release in Japanese theaters.
- 1 December: Godzilla Minus One will be released in the United States.
- 3 December: Godzilla x Kong: The New Empire is set to have a panel at the Brazilian convention CCXP.
- Kaiju: Island of Fire will be released.
This is a list of references for 2023. These citations are used to identify the reliable sources on which this article is based. These references appear inside articles in the form of superscript numbers, which look like this: 
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