This thesis discussed the influence of students’ understanding of English Lessons on their TOEFL Score. The objectives of this research are to explain the English Lessons understanding and their TOEFL Score of the 6th Semester Students of Faculty of Education and Teacher Training at UIN Walisongo Semarang in the academic year of 2019/2020, also analyze the influence of English Lessons on their TOEFL Score of the 6th Semester Students of Faculty of Education and Teacher Training at UIN Walisongo Semarang in the academic year of 2019/2020. This research was a quantitative type, which specified in correlation study and regression. The data were collected through test and documentation. The data were analyzed using regression. In this research, it was found that there was a correlation between students’ understanding of English lessons on their TOEFL score. It could be seen from correlation result that the price of t_(h )= 3.092 > t table 2.109 in 5%, correlation coefficient was significant. Regression result was that was 9.663 > 4.45 it meant that students’ understanding of English lessons had affected students’ TOEFL Score. Therefore the hypothesis was accepted. The degree of students’ understanding of English lessons was 22.79 and the degree of students’ TOEFL score were 418.84. The influence of students’ understanding of English lessons on their TOEFL score was 36%. It meant there was enough influence students’ understanding of English lessons on their TOEFL score.