The purpose of this study was to examine the effect of English language teachers' perfectionism and self-efficacy perceptions on their professional motivation levels. The research was a relational survey model and causal comparison research. The study consisted of 450 English teachers working in official primary and secondary schools affiliated to the Ministry of National Education (MoNE) in Zonguldak province and its districts in the 2021-2022 academic year. "Personal Information Form", "Multidimensional Perfectionism Scale", "Teacher Self-Efficacy Scale" and "Teacher Professional Motivation Scale" were used as data collection tools. Frequency, percentage, arithmetic mean, t-test for independent groups, one-way analysis of variance, correlation analysis and regression analysis were used to analyse the data. As a result of the study, it was found that English language teachers' perfectionism varied in favour of teachers with 0-5 years of professional seniority according to professional seniority; it did not vary according to gender and institution of employment. It was seen that self-efficacy perceptions changed in favour of female teachers according to gender, in favour of teachers with 0-5 years of professional seniority according to professional seniority, and in favour of teachers working in primary schools according to the institution of employment. It was seen that professional motivation levels changed in favour of teachers with 0-5 years of professional seniority according to professional seniority, in favour of teachers working in primary schools according to the institution of employment; it did not change according to gender. There was no significant relationship between English teachers' professional motivation levels and their perfectionism, but there was a significant relationship between English teachers' professional motivation levels and their self-efficacy perceptions. A positive, significant and low level relationship was found between perfectionism and self-efficacy perception general scores. The variables "order", "parental criticism", "parental expectations" and "effectiveness for classroom management" were found to be predictors of English teachers' professional motivation levels.