Tamio Ōki was a Japanese voice actor and narrator born in Tokyo on January 2, 1928. He began his career in the entertainment industry after the end of World War II, making his debut in 1946. He trained as a second-term student at the NHK Broadcasting Theatre Company and later worked with the TBS Broadcasting Theatre Company before joining the agency Mausu Promotion, where he remained a member until his passing. He died on December 14, 2017, at the age of 89 while undergoing treatment for an illness.

With a career spanning over seven decades, Ōki was considered one of the first generation of voice actors in Japan and was a founding member of an early voice actor union. He was active in a wide range of media, including anime, overseas drama dubbing, and narration, lending his distinctive voice to numerous characters, often generals, scientists, kings, and other authoritative figures.

Ōki is perhaps most widely recognized for his role as Section 9 Department Chief Daisuke Aramaki in Mamoru Oshii’s landmark 1995 film Ghost in the Shell and its 2004 sequel, Ghost in the Shell 2: Innocence. In the realm of classic mecha anime, he voiced Professor Sakunji in Voltes V, General Miwa and Marshal Leone in Tōshō Daimos, and Captain Tatsumi Tashiro in the OVA series Gunbuster. His early work includes the roles of Shigeru Suzuhara in the 1968 series Star of the Giants and Cozets in the 1975 adaptation of A Dog of Flanders. He also voiced Dr. Tenma, the creator of the title character, in the 1980 version of Astro Boy.

Throughout his long career, Ōki appeared in a vast number of productions. His notable roles include the King of Midland in the 1997 Berserk series, Wort in the Record of Lodoss War OVA, Dr. Woolar in Nadia: The Secret of Blue Water, Genshi Tenson in Soul Hunter, Ken-Goh in Eureka Seven, Washi (the Communicator) in Haibane Renmei, Nutouk in Macross Zero, Lazar Lobos in Legend of the Galactic Heroes, Tompetty in JoJo's Bizarre Adventure, Kikunojō Tendō in Black Bullet, and the Elder in Dinosaur King. He also voiced Juuzou Kushinada in Okamikakushi - Masque of the Wolf, Hōben in Phoenix, Albert Schacht in Mobile Suit Gundam MS IGLOO: Apocalypse 0079, the old man from Amaurot in Children Who Chase Lost Voices, Tokio in the film Hal, and Survive in Mujin Wakusei Survive.

In addition to his anime work, Ōki was a prolific voice actor for dubbing foreign films and television series. He was the regular Japanese voice for actors such as Patrick Stewart (as Professor Charles Xavier in the X-Men films), Christopher Lee, Max von Sydow, and Robert Duvall. He also dubbed George Gaynes as Commandant Eric Lassard in the Police Academy film series.

For his contributions to the industry, he was posthumously awarded a Special Achievement Award at the 12th Seiyu Awards in 2018.