A growing body of evidence suggests that teachers play a significant role in the process of foreign language teaching and learning. On the other hand, motivation is one of the most important pre-requisites of foreign language learning which can be influenced by many teacher-related factors such as teachers' personality characteristics and their self-efficacy beliefs. Therefore, this study was conducted to examine the relationship between Iranian EFL teachers' self-efficacy, their personality and students' motivation. Participants included 25 EFL teachers teaching in different language institutes and 75 EFL students learning English in those institutes. In this study, three instruments were used for data collection: Teachers' Sense of Efficacy Scale (TSES) developed by Tschannen-Moran and Hoy (2001), Neuroticism-Extraversion-Openness FiveFactor Inventory (NEO-FFI), and Students' Motivation Questionnaire designed by Mojavezi and Tamiz (2012). To analyze the data, Pearson correlation was conducted on the variables using the computer program of SPSS 22. Results of the analysis showed that there was a significant positive correlation between teachers' self-efficacy and students' motivation (r = 0.591, p = 0.002 < 0.05). The other finding of the study was that one of the NEO-FFI variables, conscientiousness, was found to be significantly in correlation with students' motivation (r = 0.413, p = 0.040 < 0.05). Results of the study and their pedagogical implications were discussed and recommendations for further research were also made.