Nobuyo Ōyama was a highly influential Japanese voice actress whose long and storied career made her a beloved figure in the world of anime. Born on October 16, 1933, in the Shibuya district of Tokyo, she began her voice acting career in the mid-1960s. Her debut as a lead voice actor came in 1965 when she voiced the character Punch in the Toei television anime Hustle Punch. This was followed by starring roles in several other notable early anime productions, including voicing the title character in Norakuro (1970), Hazedon (1972), and the role of Jin Kappei in the mecha series Muteki Chōjin Zambot 3 (1977).

Ōyama is most famous for providing the voice of the titular robot cat from the future, Doraemon, in the TV Asahi anime series that began airing in 1979. She continued in this role for an extraordinary 26 years, becoming synonymous with the character for a generation of fans across dozens of television episodes, theatrical feature films, and video games. Her unique, slightly raspy voice became so iconic that she is often regarded as the definitive voice of Doraemon. She voiced the character through her treatment for colon cancer, which was diagnosed in 2001, until her retirement from the role in 2005. In addition to her voice work, she was also active as a singer, and a Doraemon record she performed sold over one million copies, earning a Gold Disc award.

After stepping down from the Doraemon franchise, Ōyama took on another memorable role late in her career. From 2010, she voiced the villainous bear Monokuma, the main antagonist of the Danganronpa video game and anime franchise, including the television series Danganronpa The Animation in 2013. For her extensive contributions to the industry, she received numerous accolades. In 2005, she won the Broadcasting Woman Award, and in 2007, she received a Lifetime Achievement Award at the Tokyo International Anime Fair. Following her death on September 29, 2024, at the age of 90, she was posthumously awarded the Chairman's Special Prize at the 48th Japan Academy Film Prize in recognition of her outstanding, long-term achievements in the film industry.