Yoshiko Iseki is a Japanese voice actress born on January 19, 1970, in Kanagawa Prefecture. She began her career in the voice acting industry in 1996 and has worked as a freelance talent, meaning she is not permanently affiliated with a specific talent agency. She is a graduate of Waseda University.

Iseki is recognized for her role as Pakunoda, member number nine of the Phantom Troupe, in the 1999 anime adaptation of Hunter x Hunter. Another notable and recurring role is that of Kagamiyama, a member of the Screws, in the Medarot franchise. She voiced this character in the original Medarot anime series, its sequel Medarot Damashii, and several related video games including Medarot 2, Medarot 3, Medarot 4, Medarot Brave, and Medarot Navi. Her involvement with the Medarot series also included performing on a character song CD released in 1999.

Beyond these roles, her career includes a wide range of voice performances in television anime, original video animations, and video games. Some of her other television credits include roles in series such as Medarot (as a boy and a student), Zipang (as Saeko桃井), Capeta (as Satoru and Tarou), Mushishi (as a woman, a mother, and various villagers), and the 2018 series Forest of Piano (as Tayama). In the video game realm, she is known for voicing the character Oka Ohba in the promotional videos for the Ace Attorney series.

In addition to her voice acting work, Iseki has been involved in musical activities. She formed and performed as the vocalist for a music unit called neko-maji, alongside fellow voice actress Naoko Shiraishi and composer Tomiko Minami.