The method of the research was defined as the descriptive survey model since it was aimed to test whether the personality traits of teachers are a significant predictor of their psychological capital levels in this study. 416 teachers (60.3% female, 39.7% male) who were teaching in the schools of Ministry of National Education in Istanbul and were selected by simple random element sampling method constituted the study group of the research. While 37.3% of teachers who participated in the research were working in primary schools, 39.2% of them were working in secondary schools and 23.6% of them were working in high schools. In the research, the personality traits of the teachers were measured by "adjective based personality test", and their psychological capital levels were measured by "organizational psychological capital" scale. Pearson correlation technique and multiple linear regression analysis were used to analyze the collected data. Research results showed that there was a positively significant relationship between extraversion, agreeableness, conscientiousness and openness, which are big five personality traits of teachers, and optimism, hope, resilience and self-efficacy, which are the sub-dimensions of the psychological capital scale, and that there was a negatively significant relationship with neuroticism personality trait. According to the findings obtained as a result of prediction analyses, personality traits were found to be significant predictors of optimism, resilience, hope, and self-efficacy, which are the sub-dimensions of the psychological capital scale. The results obtained from the research were discussed within the frame of the relevant literature and suggestions were offered for future researches.