Sergio Masieri is an Italian actor and voice director, primarily known for his extensive work in dubbing foreign productions for the Italian market. Born Sergio Giorgetti on July 1, 1943, in Prato, Italy, he began his career as a stage actor in Milan in 1965, performing with various theater companies.

In 1983, Masieri expanded his professional focus to include voice acting, working both as a dubbing actor and a dubbing director. He founded and served as the managing director of the Milan-based dubbing company DDE - Divisione Doppiaggi Edizioni.

As a voice actor for anime, Masieri provided the Italian voices for numerous characters. His roles include Raiden in the film Ai City, Dott. Sawaru Ogekuri in the OAV Ogenki Clinic Adventures, and Iwai, the titular character in Seigi wo Aisuru Mono Gekkō Kamen. His other notable anime credits include Dakuan in Ninja Scroll, Thunder in Sonic Soldier Borgman, Mujaki in Urusei Yatsura: Beautiful Dreamer, Crystal Boy in Space Adventure Cobra - The Movie, and the Count's Messenger in Vampire Hunter D. He also voiced characters in series such as Capeta, Golgo 13: The Professional, and Planet Robot Danguard Ace.

Beyond anime, his voice work extended to live-action dubbing for film and television, providing the Italian voices for actors such as Klaus Maria Brandauer and Richard Dreyfuss in various productions.

Masieri was also highly active as a dubbing director, supervising the Italian-language adaptations for a significant number of anime titles. His directing credits include the films Ai City, Ninja Scroll, and the second dubbing of Lupin III: The Castle of Cagliostro, as well as the OAV series Idol Defense Force Hummingbird, Ogenki Clinic Adventures, Patlabor, Sonic Soldier Borgman, and many others. He continued his work in theater into the 2020s, both as an actor and director.