In recent years, especially with the outbreak of the Coronavirus, social media has become a platform for interactions with user-generated contents among online communities. Despite undeniable advantages of social media in individual and social domains, its applications have also confronted human society with numerous ethical issues. Since these issues have been less focused by researchers, the present study intends to identify and prioritize ethical challenges being posed by social media. As such, a sequential mixed research method has been applied to reach the desired outcome. At first, after reviewing the existing literature on technological ethics in general, and social media ethics in particular, ethical challenges is defined and classified. Thereafter, a survey method is used to assess and localize the challenges identified by experts. The statistical population in both stages is professors and experts of information technology and social media, who were selected by the purposeful (judgmental) sampling method. The results indicate 7 main dimensions and 42 indicators in social media ethics such as: privacy/confidentiality, psychological/social effects, cyber bullying, accuracy (information content), intellectual property, and freedom of expression issues. The findings can provide policymakers in the field of technology with a comprehensive insight into the challenges of using social media and its importance.