Purpose The purpose of this paper is to investigate the possible relationship between novice vs experienced EFLs teachers’ Big Five personality traits, ambiguity tolerance and risk taking. To this purpose, 30 teachers of TEFL courses were randomly selected, and three instruments of NEO Five-Factor Inventory, Ambiguity Tolerance Scale and Risk-taking Propensity Measure were employed to measure their Big Five personality traits, their ambiguity tolerance and risk taking, respectively. Design/methodology/approach The study was a quantitative ex post facto study. The first phase of the study was to investigate the relationship among variables of the study. On the other hand, the second phase of the study examined the impact of experience of teachers on their risk taking and ambiguity tolerance. Findings The results showed that the more experienced the teachers are, the less risk they take and the more ambiguity tolerant they are. On the other hand, the less experienced the teachers are, the more risk they will take and the less they can tolerate ambiguity. The findings of this research can have useful implications for teacher training programs as well as teaching practices. Originality/value This study can add to the circle of knowledge and enhance theoretical assumptions of the field. Moreover, considering the Iranian context, a few studies have focused on the importance of uncovering relationship between five big personality traits and teachers’ personality factors. Therefore, this study is an attempt to investigate the relationship between the Big Five personality traits of teachers and their ambiguity tolerance and risk taking.