In the Quran, God uses the word shakelah (rule of conduct) to refer to man’s robust characters; durable, exhaustive behavior patterns; emotions and thoughts and introduces Himself as his creator who has full knowledge of his developed and disorderly characters (Surah al-Isra, 84). Accordingly, it can be argued that the Quran, as the word of revelation, and hadith, as a supplemental source of revelation, can be used as resources to diagnose and treat various personality disorders. However, what they offer is not similar to what is presented in psychology in separate chapters and under specific titles and topics, but rather they include scattered teachings in different verses of the Quran and traditions from the infallibles, which need to be carefully extracted and studied. Relying on Islamic teachings, this article offers the results of reviewing the Quranic and hadith teachings related to narcissism and explains its nature, its causal factors and the traits of those who suffer from it. Based on the results of the present study, twenty-three traits of the people suffering from narcissism, including fantasizing, megalomania, egotism, self-deception, aggression, etc. were extracted and explained comprehensively and coherently.