Mami Kosuge is a Japanese voice actress affiliated with the agency Production Ace. She was born on October 20, 1972, in Tokyo, Japan. She began her career under the agency ARTSVISION before moving to her current agency. Kosuge is married and has a child.

Her career spans a wide variety of roles in television anime, original video animations, films, and video games since the late 1990s. One of her earliest and most significant roles was as Kotoko Minazuki in the popular PlayStation game Tokimeki Memorial 2 in 1999, a character she would reprise across multiple related games and drama CDs. This established her as a familiar voice in interactive media.

In anime, she is known for portraying a range of character types. A notable role is that of樱井泉 (Izumi Sakurai), the constantly flustered and easily frightened English teacher in the acclaimed 2011 comedy series Nichijou - My Ordinary Life. This performance highlighted her ability to bring comedic and endearing vulnerability to life. Other prominent television roles include高良由香里 (Yukari Takara) in Lucky Star (2007), 真仪瑠纱鸟 (Satori Magiru) in the Seitokai no Ichizon (Student Council's Discretion) series (2009, 2013), and 西田顺子 (Junko Nishida) in the Saki franchise (2009-2014).

Beyond these, Kosuge has contributed her voice to numerous other productions, often in supporting or recurring roles. She played州崎由希 (Yuki Suzaki) in D.N.Angel (2003), 红桃华 (Touka Kurenai) in Grenadier - The Senshi of Smiles (2004), and 石蕗紅羽 (Kureha Tsuwabuki) in Stigma of the Wind (2007). In the 2012 series Upotte!!, she voiced the character Jiisuri, a personification of the G3A3 battle rifle. She also played Core in Kiddy Girl-AND (2009) and Bathyscaphe in The World of Narue (2003). Her work also includes the role of Motoko Kouzuki in the Kimi ga Nozomu Eien ~Next Season~ OVA series (2007).

Kosuge's filmography extends to foreign language dubbing and drama CDs, demonstrating the full scope of her profession. With a career active for over two decades, Mami Kosuge is recognized for her versatility and her contributions to a wide array of Japanese animation and game franchises.