Yōko Sasaki (佐々木曜子,Yōko Sasaki) is one of the students from Class 3-2 during the second season of the anime.
Yōko has been Yui Hirasawa's classmate since their first year in high school. She is a gentle and quiet girl, but when she becomes fixated on something, the world around her disappears. She is a bona fide member of the Mio Akiyama Fan Club and also the only one from Class 3-2. Her admiration for Mio knows almost no limits, but Mio's "extremeness", as Ritsu Tainaka called it, is also too much for Yōko to handle.
Yōko is a girl of average height with long green hair which is tied to two braided pigtails, falling over her shoulders. The end of each braid is decorated with a yellow hair tie. Her eyes are yellow. As a Sakuragaoka High School student, she is usually seen wearing the school's uniform properly with grey socks.
Yōko writing a test alongside her first class in high school.