Psychometric properties of irrational beliefs associated with narcissism scale in university students Abstract The research aimed to investigate the psychometric properties of irrational beliefs associated with narcissism scale in university students, and to reveal differences in the irrational beliefs associated with narcissism that are attributed to some demographic variables. The sample consisted of (596) male and female students at the undergraduate and postgraduate levels, Zagazig University, their ages ranged between (19-30) years, (with an average age of (22.86, Sd. 2.94). The results showed that the scale consists of four main dimensions: trust beliefs, eligibility beliefs, conditional claims beliefs, and interpretive beliefs. The scale has a high degree of internal consistency, with high stability indicators; It ranged between (0.740-0.915) for the dimensions and (0.951) for the total score using the Cronbach, Evidence of the scale’s validity was verified using confirmatory factor analysis and correlational validity. The results also showed that there were statistically significant differences at the level of (0.01) in the total score of the scale and its dimensions in favor of males, Compared to females, there were statistically significant differences at the level of (0.01) in favor of university students under (21) years old in the total score of the scale and two dimensions (beliefs of trust and beliefs of eligibility), compared to university students older than (21) years old, and there were statistically significant differences at the level of (0.01) in favor of married university students in the total score of the scale and its dimensions compared to single university students, and in light of the efficiency of the scale in identifying irrational beliefs associated with narcissism, the researchers recommend using the scale in conducting future research and studies, employing it in psychological counseling centers and psychiatric clinics, and re-codifying the scale on other samples. Keywords: Irrational beliefs associated with narcissism, Irrational beliefs, Narcissistic personality disorder, University students.