Mary Tilford in Lillian Hellman’s The Children’s Hour (1934) and Eliza Doolittle in George Bernard Shaw’s Pygmalion (1912) share certain similarities. The two female characters from the two of the most famous modern dramas of the twentieth century are both teenagers who receive a certain period of residential education from two competent instructors, respectively. Their initial appearances in the plays are far from elegant. Yet, in a surprising twist during the course of the plays, low-class flower girl Eliza brings a miraculous success to her teachers, while Mary causes ruin and suicide in hers. The starkly different courses of change the two characters take are worth examining from a pedagogical perspective as their transformations occur while they are in a residential education environment under the heavy influence of their instructors. This essay thus focuses on the relationships the two girls have with their tutors and provides an analysis of how their behaviors are affected by such relationships. It also discusses the workings of self-fulfilling prophecies in both dramas by exploring the traces of teacher bias as well as differential treatment and stigmatization of students with an aim to highlight the works’ implications for today’s Korean educational field in today’s Korea.