The objective of this research was to find out The Influence of Aptitude Factor on Students’ Achievement in Learning English. This research was conducted at ninth grade of MTsN 1 Pati of academic year 2021/2022. The researcher took IX-A and IX-B as the trial sample to measure validity and reliability of research instrument and the researcher chose IX-C,D,E,F,G,H,I & J as the sample of the research. In collecting the data, the researcher distributed the questionnaire. This research design was quantitative. The data was found that reliability of language aptitude factor was 0.819. It meant that the languge aptitude factor instrument was reliable. The result of reliability of students’ achievement in learning English was 0.941. It meant that students’ achievement in learning English was reliable. The research’s result can be interpreted that language aptitude factors influenced students’ achievement. It meant the students who had better language aptitude could achieve the goals in learning English more easily than the students who didn’t. It was also found that internal and external factors of language aptitude simultaneously contribute students’ achievement in learning English. Additionally, internal factors have greater contribution than external factors in students’ achievement.