The rapid expansion of social media has created new opportunities for university students to communicate, learn, and participate in public discussions, but it has also increased their exposure to misinformation, discriminatory content, and online hate speech. This study examined the influence of Pancasila-based social media literacy on digital ethics and preventive behavior toward online hate speech, including the mediating role of digital ethics. A quantitative explanatory design was employed involving 250 Indonesian university students selected through purposive sampling. Data were collected using a five-point Likert-scale questionnaire and analyzed using partial least squares structural equation modeling. The findings demonstrate that Pancasila-based social media literacy positively strengthens students’ digital ethics and preventive behavior toward online hate speech. Digital ethics also positively contributes to preventive behavior and partially mediates the relationship between Pancasila-based social media literacy and hate-speech prevention. These findings indicate that critical social media competencies become more effective when integrated with humanity, tolerance, national unity, deliberation, and social justice. Universities should therefore incorporate Pancasila values, digital ethics, fact-checking activities, and hate-speech prevention into contemporary civic education and collaborative digital citizenship programs.