Guided by the organizational justice theory and emotional response theory, this study aimed to investigate students’ emotional and behavioral reactions to teacher injustice in an unexplored context, i.e., English as a foreign language (EFL) instruction. Employing a phenomenological design, the researchers collected data from a heterogeneous sample of 55 undergraduates studying English-related majors in Iran, using a free-response questionnaire. Analysis of qualitative data in MAXQDA through an inductive approach to thematic analysis presented two themes: (1) Emotional Reactions and (2) Behavioral Reactions to classroom injustice. Particularly, experienced injustice evoked students’ negative affect, reflecting their undermined psychological self-image (e.g., feeling worthless, weak), undesirable internal feelings (e.g., feeling hopeless, frustrated, anxious), dejection with how the teacher interpersonally treated them (e.g., feeling discouraged, disregarded, embarrassed), and lowered attitude toward the subject, teacher, and educational system. Furthermore, teacher injustice was powerful enough to influence students’ academic conduct as they demonstrated a range of passive (e.g., silence, acceptance, inaction), debilitative (e.g., complaining, demotivation, talking angrily), and facilitative behaviors (e.g., defending one's rights, behaving respectfully). Findings of this study imply that, as a core professional trait, justice should permeate all aspects of teacher demeanor because its absence diminishes the affective and social climate of the classroom. Thus, it is necessary that educational administrators set a systematic system of monitoring teacher inconsistent grading, favoritism, and bias, aiming for professional development rather than punitive control. As a result, regular teacher-training courses can be held for teachers who fail to follow the justice principles set by the educational institution.