Mari Adachi is a Japanese voice actor and singer born on August 10, 1971, in Kyoto Prefecture. She began her career in 1993 and is currently affiliated with the talent agency Accent. She was previously associated with Aoni Production. Adachi is known for her warm and versatile voice, often portraying characters such as mothers or kind older sisters, and she is also recognized for her use of the Kyoto dialect in her roles.

Adachi has built a diverse portfolio across anime, original video animations, and video games. Among her notable roles is Kaori Asakura in the 1998 OVA series Yu-No. She also voiced Uzume in the 2004 OVA series Shadow. In the game adaptation Dōkyūsei 2, she played the role of Misato Nonomura. Her filmography includes the role of Tsugumi Tsugashima in the Refrain Blue OVA series, Asami in Animal Crossing: The Movie, and Suzu Chiga in Detective Conan: Crossroad in the Ancient Capital. In television anime, her credits include Onpu's mother in Magical DoReMi, Li Mayumi in Digimon Tamers, and roles in Mushi-Shi and Deaimon: Recipe for Happiness. More recently, she voiced a small role in the 2024 film Great Pretender razbliuto.

Beyond animation, Adachi has contributed her voice to the Japanese dubs of foreign works, including providing the Japanese voice for Wonder Woman in animated projects such as Injustice: Gods Among Us. She is also an accomplished singer, having performed theme songs for anime and games; her single Every Brand-new Day was used as the opening theme for the anime Kakyuusei. Additionally, she works as a narrator for documentaries and television programs. Her hobbies include playing the flute and bass fishing, at which she has reportedly appeared as a television reporter.