Teacher reflection is a salient activity which can assist teachers in getting a critical view about their effective teaching (Loughran, 2010). Among various factors that influence the teachers' reflection, teacher's Pedagogical Knowledge Base (PKB) can be considered of great significance. The current study sought to investigate the relationship between Iranian EFL teachers' PKB and their reflection. Further, the predictive power of PKB components in relation to teacher reflection was examined. In this mixed methods design study, 108 EFL teachers completed the teacher reflection (Akbari, Behzadpoor, & Dadvand, 2010) and teacher's Pedagogical Knowledge Base (Akbari & Dadvand, 2014) questionnaires. In the qualitative phase of this study, 20 male and female EFL teachers with high and low PKB were interviewed to extract their perceptions of reflection and reflective practice. To analyze the data, Pearson Product-moment correlation coefficient was run and the obtained results showed that there was a significant positive relationship between teachers' PKB and reflection. Besides, by running multiple regressions, it was revealed that the teachers' PKB can predict the teacher's reflection significantly.