Ikuo Nishikawa is a retired Japanese voice actor born on September 11, 1940, in Ehime Prefecture, Japan. Throughout his extensive career, he was affiliated with the talent management firm Production Baobab.

Nishikawa was known for his wide vocal range, portraying a diverse array of characters over several decades. In the early part of his career, he frequently took on heroic leading roles, such as the titular character in Casshan and the lead in Red-Lights Sasuke. As his career progressed, he became equally well-known for voicing villains, authority figures, and eventually, a great number of kind-hearted or timid elderly men.

Among his most prominent anime roles are Azuma Tetsuya, the hero Casshan in the 1973 series Casshan; Tarou Sarumaru in Brave Raideen; and Jim in the World Masterpiece Theater adaptation The Adventures of Tom Sawyer. He also voiced Robert J. Hanner in The Irresponsible Captain Tylor and the President of Darkness in Doki Doki Densetsu Mahōjin Guru Guru. In the OVA Jigokudō Reikai Tsūshin, he played the role of Jigokudō no Oyaji (the old man of Hell Temple), and in the 1986 film Itoshi no Betty Mamonogatari, he voiced the character of Great-Grandmother. He also played Kiroku Matsuzawa in the OVA Ishii Hisaichi no Daiseikai.

In later years, he became recognizable to newer generations of anime fans for roles such as Fukasaku, the wise elder toad in Naruto: Shippuden, and Glen Mackenzie in Fate/Zero. His voice work extended beyond animation to include dubbing foreign films and TV dramas (like Prison Break and L.A. Law), as well as providing voices for characters in tokusatsu series such as Ultraman Taro and video games like Odin Sphere.

Outside of voice acting, Nishikawa had a notable personal interest in making takoyaki. He once operated a takoyaki stand in a shopping district in Tokyo's Ōta Ward, a unique sideline that was featured on a Japanese television program in 2008. He continued the business until its closure in late January 2015.

Ikuo Nishikawa retired from the voice acting industry in 2017. At that time, he stepped down from long-held roles, including his part as the father of the protagonist in the long-running series Nintama Rantarō, with his characters being succeeded by other voice actors.