The aim of this study was to compare the personality traits and defense styles of students (girls) with high and low academic performance in Ardabil city in the academic year of 2020-2021.The research method is causal-comparative In this regard, the number of students with high educational performance of 30 people and students with low educational performance were selected as well as 30 students using a multi - stage cluster sampling method. To collect research data, the five-factor personality test (short form) and the defense styles questionnaire of Andrews et al. were used. To analyze the collected data using SPSS-20 software, descriptive statistical methods including mean and standard deviation were used and also standby statistical methods including multivariate analysis of variance were used. The results showed that there is a significant difference between students with high and low academic performance in some personality traits and defense styles so that. The students with high academic performance in the personality traits of extra version (p<0.044) and conscientiousness (P <0.45) got higher scores and students with low academic performance in the personality traits of neuroticism got higher scores. The results also showed that in developed defense styles students with high academic performance (P <0.012) had higher scores and the students with low academic performance in underdeveloped defensive styles (P <0.013) and psychotic defensive styles. Got higher scores. Therefore, according to the findings of the study, it can be concluded that personality traits and defensive styles have a decisive role in students' academic performance.