This study aimed to investigate the hidden patterns of moral education and explain the role of informal interactions in shaping students’ moral values. Employing a qualitative approach utilizing educational ethnography, the research was conducted through eight months of continuous fieldwork as an observer-participant in a public upper secondary school in Ardabil. Data were collected via purposive sampling with maximum variation through participant observation, in-depth semi-structured interviews with 28 participants (students, teachers, executive staff, and counselors), field notes, and document analysis. Data were analyzed using reflexive thematic analysis, and the validity of the findings was established through triangulation, member checking, and peer debriefing. The findings revealed that the hidden curriculum is reproduced through five main themes: dual authority, selective justice, strategic silence, in-group solidarity, and behavioral role modeling. These patterns indicate that unwritten power dynamics and the gap between speech and action among school staff drive students toward a conservative silence in their vertical relationship with the structure, and toward defensive solidarity in their horizontal relationship with peers. The results emphasize the necessity of revising rigid disciplinary structures, readjusting interactive practices in alignment with dialogical ethics, and reproducing authentic lived role models within the school environment.