Josephine Martz is a German actress and voice actor known for her work in dubbing international productions, particularly anime series and films, into German. Born in Hamburg in 2000, she began her career at a young age, appearing in television series such as Großstadtrevier and Bella Block before expanding into voice acting. She took part in a workshop on the "Chubbuck and Choices" acting technique in 2020.

Martz has built an extensive portfolio of voice roles in anime. She is the German voice of Sarada Uchiha in the long-running series Boruto: Naruto Next Generations, a role she has voiced since 2017. Among the specific roles listed, she voices Lola Metrose in The Hidden Dungeon Only I Can Enter, Nerva Martillo in Assassins Pride, Sonya in Bright: Samurai Soul, Kanna Hayama in Child of Kamiari Month, Kokoa in The irregular at magic high school The Movie: The Girl Who Summons the Stars, and Hitsugi Kirigaya in Riddle Story of Devil. Other notable anime credits include Akane Mizuno in Tsukigakirei, Akira Shiodome in A Lull in the Sea, Vignette April Tsukinose in Gabriel DropOut, Misaki Nakahara in Welcome to the NHK, Yuzuriha in Hell's Paradise, and Alice Tetsuko Arisugawa in The Case of Hana & Alice. Her work also extends to video games, such as voicing Strawberry Crepe Cookie in Cookie Run: Kingdom.

Her dubbing work frequently involves collaboration with German dialogue directors. For her anime roles, she has worked with directors like Tammo Kaulbarsch on Boruto: Naruto Next Generations and Power Players, Detlef Klein on projects like The irregular at magic high school The Movie: The Girl Who Summons the Stars and Die Schneekönigin, Kerstin Draeger on Nagi Asu and Blues Clues & You, and Achim Schmidt-Carstens on Riddle Story of Devil. She has also worked with Martin Brücker and Beate Klöckner on various projects.

In addition to her voice work, Martz is an on-screen actress, with a main role as Maria Brock in the series Alles oder Nichts and a role in the Amazon Prime series Die Discounter. She is also a singer and has lent her voice to numerous audiobooks and radio plays, most notably as Ida in the popular Die Schule der magischen Tiere series. Early in her career, she won a national reading contest in 2012 and has also worked as a model.