|Japanese Seiyū||Chiwa Saitō|
|English Voice Actor||Hilary Haag|
Rebecca Miyamoto is the child genius homeroom teacher of class 1-C and the main focus of the series. She has been nicknamed "Becky" by her students.
Rebecca has long blond hair that goes down to her knee caps normally kept down but sometimes in some form of pigtails. While teaching she normally wears a green collard shirt with a red tie, a black skirt, a lab coat going to her ankles and blue shoes, although this will change.
Despite being a child, or rather because of it, Rebecca acts very serious and/or grouchy to the point of being called an old man by Rei. She is rarely shown smiling and when she is it's typically not in the classroom. Despite this she will act childish, or at least more friendly, when the situation changes such as when the school went camping or when she is scared/insulted. Her attitude is also known to get better when there is pleasant weather. She takes her work very seriously and is very no-nonsense in school.