Ryōta Yamaguchi

is a Japanese anime screenwriter often associated with Studio Deen, Toei Animation, and Sunrise.

He penned a number of scripts for Sunrise's anime TV series The Vision of Escaflowne, as well as writing the movie version, Escaflowne: A Girl in Gaea with director Kazuki Akane. He also worked on scripts for the 2002 Kanon anime television series.

His other major works include Ranma ½, Sailor Moon Sailor Stars, Cutey Honey Flash, Digimon Savers, DokiDoki! PreCure, and Blue Exorcist.

Anime Television series head writer denoted in bold Madö King Granzört (1989): as Shizumu Higa Mashin Hero Wataru 2 (1991): as Shizumu Higa Mama wa Shōgaku 4 Nensei (1992) Ranma ½ Nettohen (1992) Super Zugan (1992–1993) Shippū! Iron Leaguer (1993–1994) Mobile Fighter G Gundam (1994–1995) Zenki (1995) Sailor Moon SuperS (1995–1996) Kuma no Putaro (1995–1996) The Vision of Escaflowne (1996) Sailor Moon Sailor Stars (1996–1997) Revolutionary Girl Utena (1997): as Noboru Higa You’re Under Arrest (1993–1996) Don’t Leave Me Alone, Daisy (1997) Cutie Honey Flash (1997–1998) Cowboy Bebop (1998) Nightwalker: The Midnight Detective (1998) Shadow Skill (1998) Kocchi Muite! Miiko (1998–1999) Hatsumei Boy Kanipan (1998–1999) Chō Hatsumei Boy Kanipan (1999) I’m Gonna Be An Angel! (1999) Medabots (1999–2000) Great Teacher Onizuka (1999–2000) Hunter × Hunter (1999–2001) Ghost Stories (2000–2001) You’re Under Arrest 2 (2001) UFO Baby (2001) Kanon (2002) One Piece (2002–2003) Duel Masters (2002–2003) Crush Gear Nitro (2003–2004) Diamond Daydreams (2004) Zukkoke Sanningumi Kusunoki Yashiki no Guruguru-sama (2004) Tetsujin 28-go (2004) Duel Masters Charge (2004–2006) Mushiking: The King of Beetles (2005–2006) Zoids: Genesis (2005–2006) Project Blue Earth SOS (2006) Happiness! (2006) Digimon Data Squad (2006–2007) Kono Aozora ni Yakusoku o (2007) Zenmai Zamurai (2007) Kyo Kara Maoh! Third Series (2008) Psychic Squad (2008) Hakuoki ~Shinsengumi Kitan~ (2010) Blue Exorcist (2011) DokiDoki! PreCure (2013–2014) Gaist Crusher (2013–2014) Shōnen Maid (2016) Future Card Buddyfight Triple D (2016–2017) Cardfight!! Vanguard Prime (2018–2019) Saint Seiya: Saintia Shō (2018–2019) Kochoki (2019) Cardfight!! Vanguard Gaiden if (2020) Catch! Teenieping (2020–present) Metal Cardbot (2023–present) Digimon Beatbreak (2025)

OVAs series head writer denoted in bold Madö King Granzört: An Adventure Story (1992) Ranma ½ OVA (1993–1994) Special (1994–1995) Super (1995–1996) Nightmare! Incense of Spring Sleep (2008) Tekken: The Motion Picture (1998) Gosen Zosan e (1998–1999) Oni-Tensei (2000) Arcade Gamer Fubuki (2002–2003) Mizuiro (2003)

Films Ranma ½ Big Trouble in Nekonron, China (1991) Nihao, My Concubine (1992) Super Indiscriminate Decisive Battle! Team Ranma vs. the Legendary Phoenix (1994) Sailor Moon SuperS: The Movie (1995) Cutie Honey Flash: The Movie (1997) Escaflowne (2000) Digimon Data Squad: Ultimate Power! Activate Burst Mode!! (2006) DokiDoki! PreCure the Movie: Mana’s Getting Married!? The Dress of Hope Tied to the Future! (2013)

Live action Television Kyuukyuu Sentai GoGoFive (1999–2000) Mirai Sentai Timeranger (2000) Sengoku Basara: Midnight Party (2012)

Films Mirai Sentai Timeranger vs. GoGoFive (2001) Sengoku Basara: Midnight Party Remix (2012)