Tsutomu Tatsumi is a former Japanese actor from the Kansai region, born in March 1972. He was active as a child actor primarily during the 1980s, affiliated with the talent agency Actor Pro. His early career included roles in live-action films such as Setouchi Boys Baseball Team in 1984, where he played Takayuki Yoshizawa, and My Lovely Days the same year, in which he portrayed the protagonist as a child. He also made appearances in several television dramas during this period.

Tatsumi is best known for his sole major role in anime, providing the voice for the protagonist Seita in the 1988 Studio Ghibli film Grave of the Fireflies, directed by Isao Takahata. He was sixteen years old at the time of recording, an age close to that of his character. Director Isao Takahata specifically sought actors from the Kansai region for the lead roles, as the film's story is set there. In reflections following the film's release, Tatsumi commented on the ease of empathizing with a character close in age and expressed that he would not want to live his life in the same manner as Seita. His performance, along with that of Ayano Shiraishi who voiced his younger sister Setsuko, is widely recognized for its emotional depth.

Following his work on Grave of the Fireflies, Tatsumi did not pursue a sustained career in voice acting or public entertainment. His current activities and whereabouts are unknown. In 2012, organizers of an event commemorating the film's Blu-ray release were unable to locate him to invite his participation, despite a public appeal made during a live broadcast of the event.