In the present article, through a presentation of narcissism and other concepts such as the Imaginary, Mirror Stage, and the Other from the point of view of Jacque Lacan, we try to study and analyze this psychoanalytical phenomenon in the character of Garshasb in the Garshasb-Nameh. This study shows that Zahak creates the sense of narcissism in Garshasb, because he plays the role of ‘the other’ for Garshasb. Garshasb’s narcissism reaches its climax so as to turn him into a cruel and opinionated character. His deeds and behavior such as fighting dragons, toughness, flaunting and arrogance are rooted in his narcissism. With Zahak overthrown, Garshasb’s narcissism subsides and he becomes a calm and peaceful character. In this research, the effect of his narcissism on other characters and on the overall progress of the story will be analyzed. The findings also showed how successful Asadi-Toosi was in the characterization of Garshasb and how well he had realized the psychological aspects of the character, keeping his epic and mythological attributes.