Motivation is regarded as an influential factor in the success of any activity. It plays a significant role in reaching the desired goals, including learning English. This research aims to analyze the students' motivation and factors affecting their motivation to learn English. The population of this study was 326 freshmen in nine faculties of natural sciences at Tay Do University. The quantitative data was collected through the questionnaire and analyzed by SPSS software. The results show that the students had motivation to learn English, but their motivation levels were not high. Additionally, the students had both intrinsic and extrinsic motivation. However, the latter was higher than the former. Moreover, the results also indicate factors affecting learners’ motivation. The research findings contribute to improving English teaching and learning quality in Vietnam in general and in Tay Do University in particular.