Seon-Ju Lee is a South Korean voice actress affiliated with the Tooniverse voice actor association. She is recognized for a versatile vocal range, capable of performing a wide array of characters from young boys to adult women, often bringing a signature energetic and spirited quality to her roles.

Her career is distinguished by several prominent roles in internationally renowned animated series. She is most widely known as the Korean voice of Naruto Uzumaki in the long-running Naruto and Naruto Shippūden anime series, a role she performed for over a decade. In the Pokémon franchise, she has voiced the character Satoshi (known as Ash Ketchum in some regions) in Pokémon the Movie: Volcanion and the Mechanical Marvel and Pokémon: Black and White: Rival Destinies, in addition to taking on numerous other Pokémon roles in the original series, such as Togepi, Majayong, and Choryeon.

Lee's filmography includes a wide range of other significant anime roles. She voiced Alladin in the MBC broadcast of Time Quest! and Tailmon in the MBC dub of Yadamon. Other notable credits include Urd in Oh My Goddess!, Izumi Curtis in Fullmetal Alchemist: Brotherhood, Rei Asaka in Dear Brother, and Eiki Hyou in The Story of Saiunkoku. Her work also extends to video games, where she is the voice of Avocado Cookie in CookieRun: Kingdom. In addition to animation, she has been the Korean voice for characters in major film franchises, such as Dolores Jane Umbridge in the Harry Potter series.