This case study explored the evaluation criteria applied by six supervisors of a private language institute (three men and three women) through individual in-depth interviews in an English-as-a-foreign-language context. The researchers also collected data from supervisors' observation checklists and written feedback. A thematic analysis resulted in five main themes and two sub-themes. Therefore, a tentative framework was developed, encompassing five criteria: English and Content Knowledge, Teaching Skills, Personal Traits, Fulfilling Workplace Expectations, and Parents'/Learners'/Peers' Feedback. The proposed framework can help increase language supervisors' teacher evaluation literacy.