Masami Toyoshima is a Japanese voice actress born on April 24, 1965, in Tokyo, Japan. She began her career in the late 1980s and has been active since 1988. Throughout her decades-long career, she has been affiliated with the voice talent management firm 81 Produce. Toyoshima has built a substantial portfolio of voice roles, particularly in original video animations (OVAs) and television anime series from the 1990s onward. She is often typecast in motherly roles.

Among her many credits from this era are the specific roles of Hitomi Aizawa in the series Akiko, Ayumi Ito in Zoku Gosenzo San'e, Shizue in Vixens, Aphrodite in Venus 5, Takami Ōide in F3, Seia Kannazuki in Beast City, Ayumi Ito in Masquerade, and Shoko in Etches. Other notable anime roles from this period include appearances in Sorcerer Hunters, Generator Gawl, and Crest of the Stars.

Her most internationally recognized and long-running role is that of Hanako, the mother of the protagonist Satoshi (Ash Ketchum), in the long-running and popular Pokémon anime series. She has voiced the character for decades, appearing in numerous television episodes, specials, and theatrical films such as Pokémon the Movie: Secrets of the Jungle. She also had a recurring role in the anime adaptation of Twin Signal. For some productions, particularly in the adult animation genre, she has used the alias Uzuki Masuyo.