Akiko Yoshida is the younger sister of Toshi Yoshida.
She was silent in "American Dream Factory". Grey DeLisle provided her voice in "Weiner of Our Discontent" and "Shallow Vows", but was replaced by Grace Park starting in "Best Little Horror House in Langley Falls".
- She tried out for Steve's band in "American Dream Factory" but was rejected. Toshi criticized her for not showing any leg. She tried again later, this time showing leg.
- In "Weiner of Our Discontent", Steve tries to hit on her briefly and is turned on when she violently slaps him in the face. She refereed the hot dog eating contest between Toshi and Steve.
- In "Man in the Moonbounce", she was invited to Steve's 14th birthday party.
- Akiko appeared while Toshi painted Steve and Hayley's portrait for their parent's wedding vow renewals in "Shallow Vows".
- She was dressed as Chun-Li from the video game series Street Fighter for Halloween in "Best Little Horror House in Langley Falls". Steve Smith has an apparent crush on Akiko and Akiko also showed affection towards Steve. However, when Steve convinced Toshi to stop being overprotective, she admitted she had a crush on Doug.
- Akiko is shown younger in "American Dream Factory", possibly seven or ten. She then is old enough to be in high school with Steve in "Weiner of Our Discontent".
- In "Spelling Bee My Baby", Akiko sneaks off with Steve to avoid her mother's intense college preparation, but is kidnapped by Francine when she thinks that Akiko is trying to sabotage Steve's chances of winning the Spelling Bee Nationals over Akiko. Akiko and Steve patch up their differences and fall in love, each intentionally misspelling their assigned words so neither would win.