Koji Nishida is a Japanese voice actor and narrator affiliated with the agency Sigma Seven. He is a graduate of the Doa Production training school. His career has been primarily focused on narration and voice-over work for a wide range of television programs, rather than leading roles in animated series.

Nishida's extensive narration credits include long-running and high-profile shows such as the economic news program World Business Satellite on TV Tokyo and the documentary series BS World Documentaries on NHK BS1. He has also provided narration for Drive A GO!GO! and the long-running educational program Karada Genki-ka on Nippon TV, where he appeared in the role of Dr. Shiode. His voice-over work is equally prolific, with contributions to popular information programs like The! Sekai Gyoten News and Sekai Fushigi Hakken!.

In contrast to his extensive narration career, Nishida's on-screen anime voice acting roles are relatively limited. His early anime credits include minor roles in series such as Wind - A Breath of Heart (2004) and Misaki Chronicle (2004). He later had a role in the 2011 series Dragon Crisis!. However, his most notable work in animation is in the original video animation adaptation of the novel Dogura Magura, released in 2012, where he voiced the character Eisaku Tōdō.

Beyond anime, Nishida has contributed voice work to video games, including Super Robot Taisen OG Original Generations and SD Gundam G Generation Spirits. He has also been featured in numerous drama CDs across a variety of genres, with credits including series such as Junjo Romantica, Crimson Spell, and Deadlock. His work in dubbing foreign content includes providing Japanese voice-overs for television dramas like Elementary and The Queen's Nose. He has also participated in digital comic adaptations, such as providing a voice for the character Tetsunosuke Yanagi in a Bee Manga version of Dragon Zakura.