The current study investigates the relationship between personality traits according to the big five personality factors model, academic self-efficacy and academic adaptation among Hashemite University students in light of gender and specialization. The purposive sample consisted of 546 under graduated students, 258 males and 306 females. Three scales are used: the Five Factor Model (FFM), for academic self-efficacy and for academic adaption. The results show statistically significant differences in the average of participants' degrees attributed to efficacy and academic adaption in favor of females and scientific specializations. They also show that agreeableness, conscientiousness, openness to experience, extroversion and neuroticism are most common among university students, with a statistically significant positive correlation between extroversion, openness to experience, academic self-efficacy and academic adaption and a negative correlation between neuroticism, conscientiousness, academic self-efficacy and academic adaption. No correlation was found between agreeableness and these two variables.