Matthew Kermit Miller, known professionally as Matt K. Miller and also by the stage names Kermit Miller and Kermit Beachwood, is an American voice actor, stage actor, and playwright born on February 2, 1960. He is best known for his extensive work in English-dubbed anime, particularly during the 1990s and early 2000s. His most iconic voice role is that of Tenchi Masaki, the protagonist of the Tenchi Muyo! franchise. Miller originated this role in the Pioneer Entertainment English dub of the original Tenchi Muyo! OVA series and voiced the character across numerous installments, including Tenchi Muyo! Ryo-Ohki, Tenchi Muyo! The Night Before the Carnival, Tenchi Muyo! Mihoshi Special, the television series Tenchi Universe and Tenchi in Tokyo, and the films Tenchi Muyo! In Love, Tenchi Muyo! The Daughter of Darkness, and Tenchi Forever. In addition to Tenchi Masaki, he also provided the voice of the character Yosho in several of these productions. He later reprised the role of Tenchi Masaki in 2018 for the Funimation English dub of Ai Tenchi Muyo!.

Beyond the Tenchi Muyo! franchise, Miller has a wide-ranging filmography in anime. He voiced Prettz in Final Fantasy: Legend of the Crystals, Andy Strauss in Mobile Suit Gundam 0080: War in the Pocket, and contributed voices to classic Studio Ghibli films, including a policeman and receptionist in Kiki's Delivery Service and a train engineer in Castle in the Sky. His other anime voice credits include roles in Rurouni Kenshin, Trigun, Cowboy Bebop, Perfect Blue, Pet Shop of Horrors, and Ghost in the Shell: Stand Alone Complex. In video games, he is known for voicing the character Clasko in Final Fantasy X and its sequel Final Fantasy X-2.

In parallel with his voice work, Miller has maintained a significant career in live theater. He has served as an actor, director, and playwright, becoming the artistic director of the Sacramento Theatre Company in 2010. In 2009, he received the John Gassner Award for his play Beat Aside Apollo's Arrow.